You can always take the disk out of the enclosure and mount it directly on your pata/sata, but of course that does take some work...
In my experience, S.M.A.R.T has never really said anything about reliability before it was obvious in other ways - ie., disk making clicking noises. But okay, you can miss those clicking noises in a noisy environment, and checking the "reallocated sectors count" with SMART would tell you.