I'd go with the EX1200. It's on the boundarys of what the EX700 will do according to the manufacturer, and manufacturer ratings are always a tad, shall we say, optimistic?
I agree with Adam here, tetratec are great little filters, that have good reliability and customer services. Only been on the market three years now, so long-term reliability is impossible to judge, but if reliability long-term is a good as short-term and build quality, they should all still be going in 15 years time
All the best
Rabbut