I'll disagree with IFMU's
You never have to worry about engine failure in a glider
I have to admit, I'm spoiled. Up on the hill I only need enough speed to clear the guardrail, then I have a good 800' to get to the emergency field down below. Well within the gliding range of even the pawnee. But only needing 200' to turn back for a rope break in a glider surely makes it less worrisome than an engine failure at the same spot, for a less forgiving departure path.
Plus, when I tow, I've always got the glider in mind. If the PA25 engine quits, there are parts of the tow where I'll end up in the emergency field, but the glider will always make it back. I won't put them in a bad spot. I find that true of most tow pilots.
I can't comment on the winch launch, I've never had the opportunity. It seems sportier to me, I've seen a couple.
-- IFMU