What defines a good tonearm


I'm in the market for a very good tonearm as an upgrade from an SME 345 (309). Most of the tonearms I have used in the past are fixed bearing except for my Grace 704 unipivot. I dont have a problem with the "wobble" of a unipivot, and they seem the simplest to build, so if they are generally at least as good as a fixed pivot, why wouldnt everyone use a unipivot and put their efforts into developing easier vta, azimuth and vtf adjustments, and better arm materials. Or is there some inherent benefit to fixed pivot that makes them worth the extra effort to design and manufacture
manitunc
Now that you mention it my wife and my tonearm have a lot in common. Both take a lot of maintenance and are fiddly to get just right but the results are well worth it. A great deal of synergy but adjustability and ease of set up? Not so much.
For a serious answer I have found that the execution of the particular arm is more important than the design principal chosen. Conventional arms, unipiviot arms, linear tracking arms, etc can all sound great [ or not!]. Every design principal has strengths and weaknesses and great designers can maximize the first and minimize the second. If one design principal were clearly better then we would not still see the variety of arms we do. Unless of course audiophiles were just mindlessly searching for novelty and the latest thing regardless of sound quality; what a ridiculous thought!
Stanwal,
And I guess thats my point. I mean, there are DIY unipivot arms on the web using knitting needles with material costs under $5.00 that are being touted as being more than acceptable, so how much more does it cost to make a great unipivot that is priced at $5,000.00. I know they are beautiful, and the workmanship is superb, and they have adjustability and all that, but if unipivot is the answer, why bother with the difficulty of building a fixed bearing design. Or is there some deficiency in unipivots that the fixed bearing is trying to fix.