I know making a skimmer decision is hard as hell. There's so many out there, they're so expensive and you'll find a person that loves and hates each one. Many people feel that air draw is the only measuring factor to performance, whereas I, take many other factors into consideration.
You may want to start with the pros and cons of each style of skimmer, that being beckett, needle wheel and venturi.
Becketts are a good bang for the buck for large tanks when you have plenty of room and don't mind a huge pump with noise. It'll also need much attention to keep running well. So, if you're looking to a low maintenance skimmer, I would recommend you do not get a beckett driven skimmer. I'm sure somebody will disagree, but that's my experience. I've never owned a downdraft, so I can't really comment on them.
Needle wheels are nifty in that they typically draw less power via the smallish needle wheel pumps. They're pretty quite and are fairly maintenance free. In my experience with my ASM, I had to clean the pump fairly often and also had to clean the venturi fairly often to keep it running well. The other downside is that many of the lower cost models will need some modding to pull the kind of air that you want. If the pump goes bad or the impeller needs replacing, it can tend to be costly since many of the pumps are proprietary.
I personally don't see any of these downsides with the Bermuda. I'm running my 8C with a Mag 18, which drives it wonderfully. Something like the 5c can probably be driven with a Mag 7-12 area. I've owned the skimmer for well over a year and I think I cleaned the venturi twice. I don't think I've never cleaned the pump... and it's running just as good today as the day I got it. It truly is a God send for the lazy reefer like me. I'll have to apologizes to those who will ask me for air draw as I don't have an air meter, but I believe they show some on Bermuda's web site.
I hope that helps. I'm sure it looks like I pushing to the Bermuda, but that's only because of my experience with the other styles. I can honestly say that I would never consider a Beckett skimmer again. I surely would consider a needle wheel again. In fact I think the Reeflo Dart skimmer looks great. If I didn't drop the $800 on the Bermuda, that would have been my next likely choice. I'm sure the Deltics and H&S skimmers are awesome, but I'd never drop the money on one of those as I can't justify the cost to benefit.
Best of luck