In reply to splat2million:
Think about comfort v performance, a shoe may feel like a slipper but if your foot moves in it, it's too big, has gapes, or the rubber is rubbish (and a whole host of other variables) then you won't trust your feet as much and won't enjoy climbing so much, especially on grit where placing you foot on seemingly nothing and then putting your full weight through it without it popping is an art all of its own.
Protect your shoe, keep them dry and clean, don't walk off in them and if you do, make sure the rubber is clean, really clean, before getting back on the rock.