If your riding in questionable weather then go with the T-serv. Keep in mind that all 3 of the tires you mentioned are touring tires, it would take a lot to destroy one of those before one wore out.

I have a set of the Pasela Tour Guard on my touring bike, this tire is quite a bit lighter then the Marathon and I know the Marathon would last longer but I only do light touring for now with only rear panniers no front except for handlebar bag, so my weight is almost half of what a fully loaded touring bike would normally carry. The Marathon is designed to last an average of 6,000 miles on a fully loaded bike and about 8,000 unloaded! The Pasela won't do that fully loaded, probably around 3,000 miles loaded and 5,000 unloaded. The T-serv on a fully loaded bike would have dismal mileage, around 1,500 miles. But if your not touring on them then they will be fine for about 2000 miles. I only mention all of that crap so you can see the differences of each tire.

Some people rotate their tires to extend mileage, I do, when the rear wears out I put the front to the rear and install a new tire on the front. The rear wears about 1/3 faster then the front. Those that don't like this idea say the front tire will suffer environmental damage and should be replaced when the back goes bad...that's pure marketing BS. I have a set of tires that came with a 84 Fuji I bought, they were the original tires and they don't have one crack on them. I have a MTB my wife leaves outside because she doesn't want to haul it out of the basement, the rear tire is 10 years old, after sitting outside for 10 years (not in the winter due to snow) the tire is just now beginning to show minor cracking. I've never had a road bike tire crack, of course I usually wear them out in 2 years, but I have road bikes I haven't ridden much that the tires are over 5 years old and they too are fine. Also because a front blowout can have adverse effects that can lead to a crash it's advisable to keep a newer one on the front...thus rotate.