What Turntable to buy under $600 ?

Another one to consider, a bit different from either the Technics or the P3, and even cheaper used (at most $350 total for a mint one) is a Dual CS-5000. I had one in my closet that I had never used and set up recently to in order to sell, and I was shocked at how good it sounded. Really good - it's a very balanced, neutral presentation. Also a very good-looking design if that matters - much nicer than the Technics 1200.

It has some quirks (such as a funky headshell with VTA built in and a not-so-great tonearm), but in it's favor is that yes, it's belt drive, but has quartz regulated speed control - a very unusual combination. AND it plays 78rpm! AND it has auto shut-off at the end of the lp (which is really nice for those listening/naps). I was very tempted to keep it but my wife kept the heat on me til it was gone.

A great TT for that money (with a outboard speed control)
is the Pro-Ject 1 Expression.

Lots of good suggestions here, the trouble now with the resurgence of interest in vinyl (the other day in the used shop teenagers were agog at the records - Hey take that Abba!...My God that's early Punk!" - and talking about buying record players, this is a common experience, methinks people are getting tired of convenient but untactile unsatisfactory techno-gadgets, people need hands-on experience like they need air, and remote-control and subatomic physics ain't the way) is there are too many choices, and when one factors in used 'tables and DIY projects the choices become bewildering: get ye to a shop and try to hear/see/touch some alternatives.

Stan, with respect to the Rega tonearms I dispute it: I've used my Rega RB300 with a variety of high-end cartridges over the years, and currently use it with a new Denon DL-103 (reputedly difficult), an Audio Technica OC9, a Supex 900, and a Kiseki Blue and Kiseki Purpleheart Sapphire (roughly equivalent to an upper-end Koetsu, which are also very successfully used on Regas) with no problems, not to mention a host of other cartridges over the years. I have not yet found the MC which my RB300 cannot track and since so many do in fact use the cheaper Dynavectors (10X5, DV20X) and the Benzes (Ace, Glider) of this world on them, I have trouble believing they cannot track the more expensive ones, which are more refined, not more difficult. The Roksan was the first turntable in the mid-Eighties to knock the Linn LP12/Ittok off its pedestal, and this was accomplished in combination with the Rega RB300 tonearm and pretty well every MC available on the market, especially the high-end ones. Roksan was not the only and is not the only high-end turntable manufacturer to sell their 'tables with the Rega tonearms, the upper-end Thorenses are sold with them, the Michells are sold with them, the Basis is sold with them, I had mine mounted on an Audiomeca for a while and it sounded truly excelent here, and so on. Just 'cause they're cheap (the RB250 and RB300) and very common (I know this gets boring) is no reason to underestimate them, they were revolutionary when they were first released, the new Big Bad Boy on the block which embarrassed many expensive items, people have forgotten this now they are ubiquitous and so apparently over-hyped. While various tonearms beat the Rega in various departments, none are so perfectly balanced both in terms of energy (it is more energetic than the big SMEs) and the usual audiophile obssessions with detail, bandwidth and imaging, when an MC is hung on the end of it and it is mounted to a good-quality turntable. Unless quality has gone down (I have not compared a new RB300 to my older tungsten-counterweight one, but it would be interesting), they are truly stellar and are ubiquitous precisely because they offer so much performance for so little money. High-end dealers of course don't like to hear this sort of thing, as there's not much profit in it for them, and so they and their Audio-as-Status cronies disseminate the Rega-as-Overhyped propaganda which seems to be becoming more and more common. I've been planning on buying a Dynavector 17D MKII (one of two classic cartridges remaining I want for my collection, the other being an Ortofon SPU), also reputedly dfficult, and will eventually report on its synergy with the Rega RB300.

None of the pick ups you listed are among the truly high performance cartridges I was alluding to. Those include Zyz Airy, Zyx UNIverse, Benz Micro Ruby, Shelter 90X, Dynavector XX and XV-1, vdH Colibri and Grasshopper, etc. I'm sure the 300 will track the cartridges you list but I maintain, quite accurately, that it will not extract all of the information that a better arm will.
The 250 and 300 are nothing more than entry level to mid-level performing arms. To speak of them in the same breath as world class tonearms such as Wheaton, Schroeder, Graham, etc. is not only disingenuous but bordering on heresy. Nobody but nobody with a high end reference level analog system uses the 250 or 300 simply because they are physically unable to handle elite cartridges. Sorry to hurt your feelings but facts are facts. Good luck.
S

Heresy is my bread and butter, no disingenuousness here, and "facts" as you say, are not facts, which IS disingenuousness. If the Regas can track upper-level Kisekis, then they can track upper-level Koetsus (as they in fact do). I fail to see how the list of cartridges you list differ physically so much from Kisekis and Koetsus, or indeed Denons and Audio Technicas and so cannot be tracked by a tonearm with excellent bearings and internal damping (i.e. the brilliant variable-thickness wall) and finally, proper mass-matching. Perhaps you can explain this "fact" to me. It's a new one on me that Koetsu, to name a current name, does not manufacture high-end cartridges, but evidently you read the high-end mags stuffed with over-priced new-and-improved goodies, judge by price tag and freshness (newer is better), and perhaps consider the Koetsus "passé". In recent tests/comparisons, the top-of-the-line Koetsu (Hi Fi + magazine) was not as good in some areas as the top-of-the-line Kiseki of the '80s period, there has been change yes, and improvement in some areas, but at a cost in other areas. It's easy to design for and listen for only Detail Uber-Alles, but unfortunately for you and too many misguided audiophiles, music is far more complex than that. I stand by my analysis of the extreme balance of the Rega tonearm (especially the RB300), a quality more elusive and hard to identify than the simple tinkling of bells. In other areas tonearms old and new surpass the Regas, but overall is another story. The reason most (not all) do not mount the list of "elite" cartridges you list on Rega RB250s and RB300s is simple-minded snobbery, Audio-as-Status, nothing else: these tonearms are too cheap, and hence cannot be any good, end of story. Evidently, the controversy over the quality of the Rega tonearms continues even if some are getting bored by their ubiquity: this controversy has everything to do with too high a level of performance for too low a price. And don't worry, you haven't hurt my feelings, you have heartened me to see that the Regas continue to generate some excitement, and confirm me in my opinion that price-tag and its attendant status - the reason for the controversy in the early days of its release - has far too great an impact on perception.