I have been trying to find a good pair of these speakers for almost 2 years.
The original (and 2nd generation) Mission 770 has always been one of my favorite speakers. The company refined the design through 5 generations, culminating in the Freedom 5, which sported a new, Mission designed, horn loaded tweeter, and some horrible graphics. I found the tweeter a bit (just a bit) bright, and the Freedom 4 (with the same woofer) is my very favorite.
I have been after the 737 because I suspected that it was Mission's way of keeping the 'classic' 770 design in the product lineup, while upgrading the flagship, and I was right. The 737 uses the last, most refined version of the clear polypropylene woofer (the black colour of the Freedom 4s and 5s comes from mineral polymers added to the clear polypropylene recipe). Early versions used the very good 3/4" Vifa dome tweeter (still in production, and available cheaply at Active Surplus) seen here most recently in the Snell Type Ks and also in the 707. This pair uses the even better Audax TW025A0, and I love them.
Like all Missions, the cabinets are quite light compared to the big american speakers I've been enjoying recently, but extremely rigid. The real walnut veneer is gorgeous. Mission, to my ears does almost everything that people love about british speakers right, but removes a bit of the 'politeness'. They breathe with the music, and kick in the bass.