I am interested in picking up a pair of tubular wheels, but I am wondering if the difference will be that great.

I do not race. I ride around 100 miles a week, mostly solo, for fun and exercise. No LBS is going to hire me as a mechanic, but I can do most things myself even if it takes me a little longer. How big of a pain will it be to change a flat? What if you get a flat while on the road?

What differences will I notice? Increased comfort? Handling? Are these differences big?

I know this is a subjective question, but I think a lot of board members have made the leap from clincher to tubular so I am interested to hear their insights.