Have to admit I was slow to give slinkies a try. I've never had a problem catching fish with lead. Then 3 years ago I lost 3 rigs in a row using lead trying to drift fish a favorite hole. I was infuriated to say the least. You have to remember the MOST important cardinal rule, "you can't catch a fish with your line out of the water". Since I was constantly tying rigs and not fishing a change was in order.
The next trip I started using slinkies I made myself. The feel is very different, slinkies don't translate rocks off the river bottom like lead, they provide a softer feel. Still, this can work to your advantage, making it easier to detect soft hits.
I agree with Chuck, in really fast water lead gets down quicker, making lead the ideal choice in that situation. Anything else slinkies can fish equally well and even better once you learn the difference in feel. Takes about one afternoon to get familiar if even that.
The only problem I have with slinkies is, I don't break off as much. I'd use that time to change lures/colors. Now I often have to purposely cut the rig off to change lures. How frustrating!

Many times I feel a little guilty if I don't relinquish a drift rig to the river deamons once in awhile.
Now, 90% of my drift fishing I use slinkies. I rig solid using a snap swivel. The line from the reel and leader are tied off at opposite ends of the barrel and the snap is pushed into one end of the slinkie, sometimes I make a small hole for the snap. Sliding slinkies work better with small light weights when I use bait, otherwise I don't like the fraid line that heavier weights create.
Making slinkies is easy, just make a variety of sizes to accomodate different conditions. I use two sizes of shot, .210 and .190 with .190 being the most versatile, the slim profile seems to snag less. Also, don't forget the other cardinal rule when it comes to fishing, keep it simple stuby (K.I.S.S.).
Everyone has their own preference, this just happens to be mine, at least until I or someone else figures something better.
best of luck,
Gregg