A 749 is,in theory,be a better bike than the 748.It's got,as standard, better brakes,a more powerfull Testastretta motor and more rider friendly erganomics.The only negative argument Ive heard about the bike is the looks.Some folks hate the look of the newer bike and prefer the 748/9** series shape.
Down to the individual tastes I guess.
Consider the price issue.There are some very good 748's out there for not a lot of money.For the price of a 749 you could buy a 748 and have some change to spend on accessories/insurance/gear/wife/w.h.y!
Whatever bike you choose,you wont be disapointed.