If you can afford the 3700+, get the 3700+. I have always been of the opinion that if you have the money, buy the best you can afford. Its as simple as that. Don't try and save a few bucks so you can stop off at McDonalds on the way home from work. If your going to invest all this money into a system in the first place, you might as well not cheap out.
On the other hand don't spend money you don't have
Don't spend the money and then force your children to eat Peanut Butter and Jelly for the next three weeks just so you can have an "awesome system" If you know what I mean.