I have been working with 401(k) plans for quite some time but haven't ventured into the 403(b) arena. Since the recent regulation with the requirement of documentation of 403(b)'s, what is the difference between the two in the areas of compliance and tax reporting? Are they pretty much the same now?

Pretty much the same for ERISA 403(b) plans now, other than no ADP or Top Heavy in 403(b) plans.

...and don't forget "universal availability". Oh, and there are some differences with the trust.

401(k) is a qualified plan; it's governed by I.R.C. Sec. 401(a) and its related Code sections, including the trust requirement. 403(b) isn't a qualified plan, and its assets are held in annuity contracts and/or custodial accounts and deemed to be owned by participants.

Although the two arrangements often walk/talk/seem/look the same, they're two very different "animals." You don't want to make a leap of faith and erroneously impose a 401(k) rule on a 403(b) plan, or vice versa.