I have played at BTCSportsmatch on and off for a few years now.
1. Deposits - since this is an exchange, the btc will not show up in your account until there are a number of confirms. I can't remember but I think it takes somewhere between 4-6 confirms
2. Withdrawals - withdrawals are instantaneous
3. Liquidity - for major USA sports, liquidity is OK. For major events, liquidity can be very good
See the last post in this thread for an example of liquidity on an NFL Playoff Saturday:
https://bitcointalksearch.org/topic/m.44512354. Odds - It's an exchange with a 1% fee paid by the winner. They call it a "hybrid exchange" because the odds you get is the calculated vig free line at the time the bet is matched (based on the current Pinnacle line). If the juice is -109 or less, they don't bother with calculating the vig free line (VFL) and you will get it at EVEN (+100). For example, if an NBA game is Miami Heat -6.5 -109/New York Knicks +6.5 -101 on Pinnacle, you would get -6.5 +100 or +6.5 +100. If the line went to -110/+100, you would get -6.5 -105 or +6.5 +105 because the VFL calc would kick in. You pay a fee, so remember to add that to the calculation when determining the exact amount of juice you will pay.
Being a hybrid exchange has it's pros and cons. Some in this thread say they wouldn't post offers because the line could move on Pinnacle. Well, a pure exchange has a similar problem. On a pure exchange, bots will hoover up any stale offers as soon as a line moves substantially on Pinnacle. For example, if you wanted to bet the Knicks in the above example and so offered Miami -6.5 -104 on a pure exchange, it would get snatched up immediately if the line were to move to -7.5 on Pinnacle. This was always a big criticism of Matchbook. I am not sure if they have changed their software or not.
5. Should you use it? I consider the site to be safe, so it's a must out for me. You can get bets down here for very negligible juice. If you think about it, the internet based betting exchanges should have already made sports books obsolete. The main thing holding back the exchange model is the ignorance of the typical sports bettor (most of the major bookies being old timers doesn't help either).
Crypto-currencies should likewise lead to a revolution in offshore gambling. What will hold this movement back? Also the ignorance of sports bettors, and the advanced age of the major bookmakers (they still can't get over how cutting edge using the internet to take bets is).
This site combines the best attributes of two killer apps - a betting exchange that uses a crypto-currency. It's funny that the major books have been too stupid to figure this out. It's so simple and so brilliant.
I expect liquidity should be pretty good for March Madness games. Now would be a good time to try out the site. As with any exchange, the more people who use the site, the more useful the site becomes.
Edit: Just want to mention that I am approaching this from a USA-centric viewpoint. I know about Betfair, etc. I know it would be hard for a UK regulated exchange to accept crypto-currencies. I am talking about offshore sites that ignore applicable laws.