I've used the hyway 45mm closed port kit, I've used oem cyl w/ meteor flat top pistons, golf pistons, oem 44mm kit, 346xp AM lookalike kit... I have NOT used the full meteor kit. just haven't gotten to it yet. personally, I'm not sure if one is necessarily better than the other, though the oem open port P&C is likely not the best of the bunch.
just ran my AM 346xp lookalike from ebay last night... man that thing is strong. its the AM 346xp kit from ebay, and a meteor 44.3mm piston. I like it a lot. Ran it against one of my 455's... it was AS fast or better... considering its 44.3mm piston vs 47mm for the 455 ... I think it does great, especially for the weight.
I know old cat has his opinions, so i'll let him weigh in