Both are low end protein skimmers.
My experience with the Skilters have not been very good. The 400 doesn't skim worth a hoot, and the 250 did marginally, but was still pretty lame. Both are so loud that you must go to great lengths to quiet them down. Thumbs down on the Skilters.
The Lees skimmers - although I have never used one - would not seem like a good choice for your 55 tank ( I assume this is for a 55 ). Thumbs down on the Lee's as well.
Many have reported good results with the Prizm skimmers - economical and efficient. Personally I also like the CPR product - Bak-Pak's are pretty nice - and their insump units do a decent job as well.
Guess it depends how deep your pockets are - how much you wanna spend.
Broomer