Liquidity has been good so far - better than I would have expected. At present they are only offering win markets, but I've been told that place and possibly each way markets will follow fairly soon.
Agree entirely with your point about starting prices. The system is outdated and quite frankly discredited these days and is in urgent need of reform. Bookmakers will, of course, do all they can to resist any changes because, as you rightly say above, the current arrangements offer them a large over-round and consequently a large potential profit margin.