I am going to purchase a 20-21' aluminum boat and need to decide on bunks or rollers for the trailer. Dealer seem to push the bunks because they are cheaper and easier on the aluminum hull. They claim that the new glides on the bunks make loading and unloading almost as easy as with rollers. I had rollers on my previous trailer and I was glad I paid the extra money which allowed for usage at lousy ramps where I didnt need to get the trailer as deep into the water. I want to be able to onload and offload the boat by myself. Should I spend the extra $ for the rollers or are the new improved bunk/glide systems usable at marginal ramps?