If you want ease of use, get one with a hydrostatic transmission. You pay a bit more, but it's worth it. May be slightly less reliable than one with a gear transmission, but the ease of use - especially if you're mowing with it or having to do a lot of forward/backward maneuvering - is well worth it.
One of the things I found when I owned John Deere tractors (lost them by divorce) was the fact that their dealers are everywhere, their products are easy to work on and maintain, and all parts are readily available. If my dealer didn't stock a part, he could have it the next day, most of the time. If you're not into doing your own repairs and maintenance, the dealership will do it for you - mine would even come on-site to pick up equipment.
As long as you perform the scheduled maintenance, I would say it's very common for one to last 10 years, and with care you could probably get 25 years out of one. Be prepared to pay a premium price, don't choose from the cheapest product line, and I think it's unlikely you'll go wrong. it's an investment that will pay for itself in the long run.