I had a pair of Navi xta, cracking reels... but.... I sold mine because after casting, any slack line at the reel got caught behind the spool if the spool was at the front of it's stroke( hope that makes sense?)
If you check the reel after EVERY CAST, not a problem:wh
The newer navi xsb/xtb now has a guard behind the spool, worth the extra i'd say!
I've not tried the aerlex, sorry.
I would go with the Aerlex for spodding as the the Navi is a more expensive reel. Your spod kit outfit is going to be taking so punishment, so save the tartiness for the rods on your alarms