I've used the S22 model, its considered a training tire. (The clincher compadable model would be the C S22.) I got it from my LBS for 40 bucks. I'm getting around to trying the racing models. But the S22 was pretty durable, the ride was ok, I really like the ride of a nice conti tubular or vittoria cx (BTW these cost 60 bucks a tire). The S22 is a good training/commute tire.
the sealant should be put in right-away. The core of the stem comes out and inject the some sealant and reinstall the of the stem. When I got the tufos I just carried the sealant around with me until I got a flat. It's just easier to install the sealant in my garage verse on the road.
the sealant is lightweight and stays in liquid form in the tire...until you get a flat, then the sealant finds the puncture and seals it! I was riding up a hill with 3 guys on my rear wheel when I heard the sound a tire going flat...I had the sealant installed and I kept on riding, the the sound stopped quickly and my rear tire still felt solid. I must have lost only 10psi...the guys were impressed.
Ask your LBS if they intend on carrying the full line of tufo tires, or check out:
http://www.bicycletires.com/tek9.asp?pg=tufoclinchers
I think they're pretty cool, let me know how you like them.