BOLA 2008 is real good, but I'd say 2009 is better. Although don't sleep on '08, some really fun matches on those:
Night 1 had Low-Ki/Strong, Aries/Nigel, Davey/Danielson and the 3-way sprint. All real good but not must-see.
Night 2's got Low-Ki/Yoshino (short albeit great sprint), Danielson/TJ Perkins (probably Perkins's breakout match that got him noticed and where he is now), Hero/Lost (really good), Hero/Danielson (again, real good) and the excellent Hero/Low-Ki (you can see this on PWG Sells Out II).
Now comparing that to BOLA 2009, it just seemed like 2009 BOLA had a better flow and overall match quality. Literally every single match on Night 1 is enjoyable and all deserve replays (except maybe the first 2). Omega/Steen is excellent, and Generico/Shelley is must-see for technical fans. Also Cabana's best match I've seen him in since WWE is on here (vs. Joey).
Night 2 is amazing, must-see, one of the best PWG shows ever. Omega/Lost KILLS, Gatson/Shelley is awesome with a superb upset, and the last 2 matches are 2 of the best PWG matches of all time, bar none (especially the Bucks tag).
If you're iffy on getting BOLA 2008, I'd buy night 2 at least.