Hi nmdbase, I test rode both a Five Pro and Covert recently and must say they are very similar bikes. Both are fantastic with a tendency to make you risk life and limb. IMO the Five felt slightly better balanced over technical terrain whereas with the Covert you just rode though (or over) it. The Five felt very slightly faster on flat trails and really alive downhill (that Five magic), both climb competently. This was just my analysis based on the two I tested.
The Covert I rode was around 32lb and very nicely put together (X9, X0, 160 Talas etc...), a heavier build would have started to feel a bit too rugged. I suggest you get a demo on both, if you can't you'll be happy either way. I lost a few nights sleep deciding which I wanted and ended up with a Five... But that was me. I spent a few £££ and my Five is around the 29lb mark, I also think I managed to make an inherently ugly bike look alright!
This is the Covert that I test rode.
And this is the Five I built up with the help of my LBS. Really, really