There are a ton to choose from these days and there are many that are extremely similar. DC skimmers are great for many reasons and most are utilizing the same pump's these days as well so to me it comes down to price. For your more budget DC skimmers look at the reefbreeders, simplicity, hi seas, your choice. They are all similar and work well. Your more common brand like' octo's, aquamax, skimz are all great performers as well. There are so many options out there nowadays you should not have an issue. I would look something that produces 700lph air minimum for a 90g with sump and try and get something that cycles 300gph of waterthrough. The eshopps skimmers are pretty nice as well, nothing wrong with them. I would probably avoid the hydor's due to price and performance, you can just get better value these days.