Bumping this one as I bought a brace of soap (!) from RM.com just the other day. I shower, don't do baths as I get to hot in them, and have to say the bar is holding up really well. I drain it after each use and it seems to be lasting ok. A quick skim through my hair leaves enough to work up into an amazing lather, and afterwards I feel really clean. It seems to be getting rid of all the grime from work so I am really pleased with it, and afterwards I stink just like I've left a nice fire in the woods, so a bonus there! The missus hates it, but I'm not bothered about that!
I'm thinking that one of those string bags used in the washing machine to pop the soap in would work for draining it after use, and that it could also work as a scrubber too! Hanging it up to dry would certainly help the bar last a little longer.