I have had both types of Aerostitch suits (Darien and Roadcrafter) and I have a Rev'It Cayenne jacket (I've had it for a few years - the original version, not the new one).
IMHO, both are well made jacket/suits, both work well in most riding conditions and, without a doubt, both are way over-priced. Yes, they each have some redeeming features that make them somewhat better than your cheaper options, but the reality is that those cheaper options (Tourmaster, FirstGear, Fieldsheer, Olympia, etc.) do 95% of the job, sometimes at 50% of the cost.
Personally, I like the Roadcrafter suit better than the Darien one, it's more versatile (especially if you pick the two-piece version) and it zips together for added safety. Rev'It gear will be more waterproof with the right liners in place, but if you ride in changing weather (especially hot changing weather) liners are a PITA, because as soon as it stops raining and it starts getting hot (and muggy) it's like having your own private Turkish bath...
Since I already had a rain jacket I used to wear over the Stitch when it really rained hard, I use it over the Rev'It when the weather is changing fast. It's faster to put it on/take it off road-side than the internal liner (in winter, even fall/spring that isn't a problem, the internal liner is 100% waterproof, I'm talking about summer riding above).
Unlike, siyeh's suit, mine were more of the typical leaky Aerostitch type. The Darien will be more waterproof than the Roadcrafter (Google "leaky crotch"
) due to the larger overlap of the jacket and pants. But I liked the fit of the Roadcrafter better, so I kept it and gave the Darien to someone else. It was good for short periods but eventually both leak through (as it got older, it was down to 2-3 hours tops). I am also in the camp that thinks Andy Goldfine has milked his original idea long enough, it's time he starts updating his line or he will eventually be out of business (as evidenced by me, like many others, going shopping elsewhere when it was time to get a new suit, rather than going back to Aerostitch). My biggest beef is that for that price, it is about time that they added waterproof zippers, a decent liner thermal included at the price and a couple of extra ventilation points that would make it a true all season suit.
One important detail - the fit is completely different. Darien suits are cut to accommodate "prosperous" men. A medium was too narrow in the shoulders but the large felt like a tent (my Roadcrafter suit is 42). Rev'It gear is cut for slimmer ones. I typically wear a medium sized long sleeve shirt, but a large Cayenne fits me perfectly, so you will most likely need to go one, maybe two sizes up from your normal size. If one fits you well, I'm betting the other one wont, which, eventually, may be what really makes the choice for you, more than anything else.