Mansion are ok. They are poor on game selection though. It is basically NLHE or nothing. Their action buttons take a little getting used to as well. Frankly, they need to redesign them. The dealer sounds like he is starting a motorbike when he shuffles, but hey, that's a feature.
However, the massive saving grace :-
They are great for overlays. The 100K guaranteed is just great really for any focused poker player.
1) About 50K from entrants each day, so they have been subsidising the tourneys to the tune of another 50K each day to make it up to 100k.
2) The stacks and blind speeds are very sweet. Its a very gentle plod to the money (about 4 hours). 20k for first place. Time is a little ackward for Europeans though. 8.45am finish the other day which wasnt great for the eyeballs. Better for any Americans/Canadians though.
In, summary, give them a whirl