nice thing about the ortofon OM is that you can change the stylus without changing the cartridge. i went from a 5-10 for $40,both of these are eplliptical,the 20-is n-de epllitical which gives greater frequency response(so i am told)and goes for $90 or so.*** put the letter u above n-de) on my pro-ject debut lll the sound quality was improved,also might have something to do with the speed changer(pro-ject speed box),i wish i had gone for the 20 and if i keep playing vinyl the way i have been it won't take long.good luck,and BTW changing stylus is VERY VERY easy
As Jan will tell you, I hate the OM series with a passion. Ortofon make much better things for not huge sums. Look at their new m2 series for example. Alternatively, there's the new Goldring 2000 series which is pretty good, and I have had excellent results with the Grado Prestige Gold 9although that may be overkill on this deck).
the M2 series seems a bit pricey for the TT in question....unless it is worth paying $150 or so for a cartridge/stylus for on a $ 300 TT,it seems that for the TT either rega 1 or pro-ject debut 111 the OM seris works.....is that misguided thinking? frank you know much much more about this stuff then me......just curious....
The OM "works" on those tables because Ortofon gives them a hell of a deal on a very old cartridge design. The OM series is over twenty years old and was designed for very the low mass tonearms that were available on budget tables of the day such as Dual. The OM series is outdated and doesn't mechanically work with a medium mass arm such as the Rega. So, you can upgrade the stylus on the OM cartridges but you're still stuck with an OM cartridge body in an arm it's not suited for.
You'll get much better performance from a better cartridge better suited to the Rega arm. Try the new Ortofon or the Grado. Both companies tend to have a very warm side of neutral house sound and both offer a good sized taste of their higher end cartridges at budget prices. Check with the seller that the Grado won't have hum issues with the Rega. With Rega's new motor it shouldn't but ask anyway. Or, try a Shure M97 or a budget Audio Technica. I haven't heard a Goldring in thirty years but I'd take Frank's advice on that one also.
Considering the abilities of the Rega arm, in this case, $150 is not too much for a cartridge on this table. I wouldn't go any higher but the cartridges listed here are all compatible with the Rega arm.