You are in luck... The guy in the beach slip next to me has been sailing a Nacra 5.7 for 6 years, and my father has been sailing a Hobie Getaway since 2001. So I have first hand knowledge of both.
Nacra 5.7 - The 5.0 and 5.7 are Nacra's take on a "fun" beachcat. Don't let the boardless / boomless design fool you. This 19ft'er has plenty of sail area to chase down any boat. going to wind. It can be a bear single-handed over 10mph. The deck is big and uncluttered. Really, I think it is the ideal beachcat for fun.
Hobie Getaway - Excellent boat for a guy that likes to single-hand and take 4-5 people out. With wings it is very manageable and comfortable. The big draw back is also what makes the boat so manageable: SAIL AREA... there isn't much for it's size. That being said, it is still not slow at all. Single-handed it is as fast as an H16.
Both boats are heavy (400+lb.). The faster of the two hands down in the 5.7. Comfort, it's the Getaway. Build quality, Nacra 5.7. BIG NOTE: DO NOT BUY 2001 GETAWAYS. Hobie has some real issues with the curing process of the roto-moded hulls, two-piece masts and original hull coolers. Buy a newer model if you go with a Getaway.
PS - The 5.2 is a great boat, but it is not for more than 2 people. I have a 5.2 and I'd rather have a 5.7 personally.