the PES series has never let me down. i used to be a FIFA guy (about 6-7 years ago) but after playing my first PES i never turned back.
definitely KONAMI has made a lot of improvemnets from their last title. although it fixed minor problems from the last series, it was those problems that held it form being a really good game. and the slower pace ensures that players have to be tactical and choose a formation that suits their style of play.
but the reason that it got such a low score is because of how great FIFA 09 is compared to its last title. i've played the demo and although i hate to say this, it is quite good. not PES good but far, far better than FIFA 08. and the fact that PES had little improvements compared to FIFA made some reviewers giving it a lower score than it deserves, IMO.
i bought the PC version and it has a lot of bugs in it. but that comes with a lot of PC games so im still waiting for a patch to come out. for this reason im not giving it a 9. PES 2008 had no bugs for me.