well, I flew the 738/737 but at now I fly 733/735! All of them are really nice, but the 738 was just pretty big (for a 737) which made it really stable and easy to handle... it reacts on your control inputs at once, but not to hard just smooth... the cockpit is really nice due to the 6 big screens you have in there... (and afaik they are bigger than the 320 ones
) you just look direct on the PFD and ND which have most of the information you need to fly... just the engine instrument are a bit more to the left...
I must admit that it is not very big in the cockpit of the 737 and I am pretty tall and it is not the most comfortable seat in the 737 (but the seat with the best view
The 738 had 26k/27K rated engines which gave them a good performance especially with winglets... the 733/735 I fly now are rated 20k, which is more than sufficient for 57.6 tons MTOW.... and most of the short flights we have a gross weight of about 45 tons... so: power is enough
It is nice flying them