AQ PT-9 vs. Rb250-300

I had both a PT6 and a RB300. I preferred the PT6 in every way. Although the RB300 has more upgrade options which I think is why it's more popular. I think the PT9 is a newer spec, and imagine maybe an improvement over the PT6.

What did you you like about it regarding the sound differences?

I didn't notice a material difference in sound - both are pretty neutral. The Rega arm is harder to set up (VTA is a royal pain unless you spring for the VTAF), harder to adjust (hard to set VTF accurately, and the cuing mechanism is stiff/not very adjustable). I had it mounted on a Pink Triangle table which probably was a poor match in the first place.

As Stringreen points out - if you mod the Rega it can be better, and there are more/better mods available. VTAF, and the Michel counterweight go along way to mitigate the setup issues, and make excellent sonic improvements. The only thing is, once you spend the $s for those mods and re-wiring, there are other arms to consider.

I don't want to sound like I'm bashing the Rega arm. It's a very popular arm. My observations are probably personal preference. I was satisfied with my RB300, and when I sold it, it took about 2 hours for a buyer to show up. You can't go wrong with one