They’re both great. If you can’t decide, here’s a big factor: the MB-339 is all steam gauges, while the T-45 has a HUD and some (older style) glass displays.
If one or the other of those is a big turn on or turn off for you, that may help. 
Hah! Forum must have bumped the thread for no apparent reason, i love it when it revives necro threads like that.