catfish, if you really want a rail system that's easy to clean, get a two piece. You can just take off the bottom piece and you're good to go.
Cleaning under a one piece rail system is easy if you have a high pressure hose and air compressor. Just hose it down, dry it off and spray it down with your favorite lube.
Out of curiousity, why do want to go with a rail system vs. stock handguards? What do you plan to put on the rails? Don't get me wrong, I like rail systems but I'm starting to see the advantages of stock handguards.
Please understand, as much as it may seem to the contrary, I'm not slamming you for what you want. I'm only trying to get to the real reasons why you're looking at said options. Far too many people don't communicate the reasoning behind their needs and those offering advice and opinions don't state why they have a certain preference or opinion. The end results is people are confused and will often make a less-than-informed purchase.