Another vote for Testo - had a 327 now got a 320. Does a lot more than just fga if you get the optional sensors, and service costs are reasonable. Whatever you choose buy it from a reputable retailer, got my Testo off amazon to save a few quid and it turned up with European software, took it to Testo service centre and they swapped out the software and issued a new calibration cert for nowt, but cost me half a days work.