Difficult to put on. The secret is have no doubt. Make sure you don't pinch the inner tube and give yourself a puncture before you even get on the road. Lots of videos on Youtube.
An interesting one shows it being ridden over crushed glass and tacks.
If u can only afford one tyre put it on the back. Most of your weight goes there.
Wiggles describe the Schwalbe Marathon Plus as "the only true flat-less tyre".
Don't be put off by comments about "high rolling resistance". Pump them up well and you'll fly. In any case, you'll go a heck of a lot faster than if you have a flat.