The only drawback of DBPro is that it requires all the latest Video drivers, and the latest version of DirectX ( 9.0b ) and a relatively good video card. If you have a computer that is about 5 or more years old, then you might have to upgrade your vid card. But otherwise, you should be alright.
DBPro doesn't run code slower, you are right, It runs slower on older machines, but if you were to use Hello World for example on a reletively new machine ( Mine is 4yo and it runs fine ) in both DBC
and DBPro while timeing it, you would notice that DBPro does run faster.
Atm, in DBPro there are a few compiler issues that make very large exe's, but they are hoped to be sorted out in Update 6 ( unofficially due mid-feb )
The good thing about DBPro is it's expandability, the way you can simply add commands to the language by just dropping a DLL into a folder. It is a very good engine ( The DBPro Core ) and is quite strong, and with Update 6 on it's way, it is set to bring alot more powerful and usefull commands.
THe bottom line:
If you want to make games that run on older machines ( Or you, yourself have a really old machine ) then go for DBC.
If you want the power to add to the syntax of DBPro and have access to its multitudes of new commands compared to DBC, and you want access to
free upgrades, then go for DBPro
But, it's your choice.
Hope I Helped...
Team EOD :: Programmer/Logical Engineer/All-Round Nice Guy