Best Ortofon?


I'm ordering a Rega P1 with a Rega MM Phono Pre (used). The P1 comes with the Ortofon 5E cartridge. As I understand it, that cartridge has the same electronics as the 10, 15, 20, 30, and 40, so I'm thinking of upgrading by just buying a new stylus. The prices are:
15 for $60
20 for $100
(30 for $140)

I'm probably going to do the 15 or 20. Do you think these are a big improvement over the 5? Is the 20 a big improvement over the 15?

I'm also thinking of the glass platter upgrade for $69. Will it be a noticeable difference, esp versus the stylus upgrade?
arlipton
Thanks very much for the detailed and helpful response. So I want to throw one more option in there: What about the Rega Bias 2 vs the Ortofon 2M Red vs the Ortofon OM20? I though that, since I'm using the Rega P1 and Fono pre, maybe it would make sense to consider the Rega cartridge as well.
I owned the Elys, which is the next step up from the Bias, and found it rather dry and dull. I think most people tend to be disappointed in Rega cartridges with the exception of the Exact, which is around $700 now. Also, bear in mind that Rega cartridges do not have user replaceable styli. When the stylus goes, you need to send it out to be professionally re-tipped or exchange it for a new one. If you're new to analog, and not yet comfortable mounting and aligning a phono cartridge, this could be a big negative.

The OM20 is a nice cartridge but it is basically discontinued. The OMN series dates back to the early 1980s and was really designed for the low mass arms of that era. The 2M Red is a more advanced overall design that is a far better match with the Rega arm. The Rega Fono should work fine with it. I guess you might say that the OM20 is more 'listenable' but it leaves me wanting more.

If you find a dealer that sells both Rega and Ortofon, you might be able to negotiate a slight package discount -- maybe 10% -- by buying both at the same time, and as a bonus, they will mount the cartridge for you. I would try Bess at Music Direct, if he's still there, assuming you don't have a dealer in your area.

When the 2M Red stylus wears out, you can always upgrade to the Blue stylus unit as it is interchangeable. You may not want to.
So does the 2M Red mount easily to the P1's tonearm? BTW, I'm pretty handy, so if the dimensions are good, I can probably do a good job. Thanks again.
Any cartridge should mount easily on that arm. You should have no problem at all. But, again, if your dealer sells both brands he should do it for you at no extra charge.
If thats your price range. I'm currently sold on the 2M Red, I know its not a nude eliptical, but I am blown away with its performance.

and Like Ekobesky said, when you out grow the Red you can just upgrade the stylus to the Blue or Bronze with practially no effort.