I think it comes down to the CDMA or GSM issue. Onyx probably a better phone, but it's GSM only. Also the Onyx is not as close to being released and the final specs may not be set. Tour will be the best phone you can get on CDMA (unless you want touch screen), and coming much sooner. No wifi, and the processor will probably be less than the Onyx.
Ah, I misread his post and thought he meant it was a 2G phone and GSM as well.
Despite the limitation some GSM users will buy unlocked Tour's and use them on ATT & Tmobile, but I agree with others that they are MUCH better off waiting on the Onyx OR getting a Bold.
Seeing as how most of Europe is on GSM networks, I'd venture to say that the OP is best off waiting for the Onyx if he/she doesn't have a pressing need to get a new phone.