This thread deals only with the debate of which organization had better fighters, not which organization is better. If you don't think ranking fighters is important then leave.
The reason why the Pride vs. UFC debate was and still is valid is because it was the basis by which we rightfully determined who deserved the #1 spot at 205 and HW in the past based on how things have worked out today. Bushido is not meant to be discussed here. Rather than casting blanket statements about groups of fighters we will look at the fighters at the time that people were arguing about.
205 Weightclass UFC
2000: Tito def. Wand by decision. This fight becomes the cornerstone for the UFC #1 debate at 205.
2003: Randy def. Tito for interim and then Liddell for undisputed title.
2005-6: Liddell def. Randy Twice
205 Weightclass Pride
2000-6: Wand was champion this entire time.
So let's take a look at the specific claims from the UFC #1 side and see which are debate-able today:
Tito better than Wand - This is now laughable. 90% would agree Wand takes this today.
Randy better than Wand - This is debate-able and unfortunately will never be settled.
Liddell better than Wand - This will be settled very soon.
205 Synopsis: Aside from the fact that Rampage has dethroned Liddell claiming the UFC title for Pride fighters (those who debate this fact are being dishonest) the Pride vs. UFC debate at 205 is largely riding on Silva vs. Liddell. This is a very important fight for MMA fanatics as it could either A. definitively prove Pride had better 205's or B. Show that the Liddell defs. Wand crowd was right although it wouldn't change the fact that Rampage now has the 205 title.
Heavyweights UFC
2002: Rodriguez
2003: Sylvia
2004: Mir
2005: Arlovski
2006: Sylvia
Heavyweights Pride
2001: Nog
2003: Fedor
HW Synopsis: There simply have not been enough fights yet to draw any conclusions. We'll probably never get to see Fedor fight the top UFC guys from that time, but Nog has the opportunity to at least debunk any Arlovski defs. Nog or Sylvia defs. Nog claims.
In conclusion, Pride seems to be winning the "who deserved the #1 205" question for now but Liddell could still change that. HW is a mess and if Nog destroys everyone then it'll be clear Pride deserved the #1 spot at HW but if he doesn't then we'll probably never know since Fedor is the harder test.