I have both the 727 and the 737.  I like the 727 a bit more, because I like the RW 727 so much.  What lines!   It is a stunning aircraft, both on the ground in in the air.  

I had to purchase Acceleration to get the AP to work properly.  Like BrianG said, once you have the Michael2 and Paul mods done, it is really a great flyer.  I've always loved hand flying this one.

I really like the 737 as well.   I hope the update is worthwhile.  (Aren't we still waiting on 1.5 for the 727?)