I would use the one that ships with your device for a couple days to get an appreciation for how the "stock" version runs. Then I would update to the latest although many will say 237 is the safe bet I have not had any problems with 241 and will be loading 244 today myself. Just be sure to follow the instructions found on this site exactly, delete the vendor file and use DM 4.6 not 4.7.
Good luck.
Posted from my CrackBerry at wapforums.crackberry.com
I suggest you stick with the one it comes with. If you begin to have problems with what you might think be OS related you can always post us in the Bold forum. Of course you'll try a search beforehand.