There are 3 exchange options for US customers: Betmaker, Matchbook and the Parlaymakers Exchange. I thought a quick review of each and discussion would be worthwhile for everyone.

Betmaker - backed by CRIS
Deposit methods - VC, wire, Neteller, Moneybookers, **/**
Deposit fees - depends on method but according to their live chat 8% for VC, 3.9% for Neteller, 3.5% for Moneybookers, $15 flat for ** or **
Withdrawals: By above plus check
No rewards or other promotional programs
Commission: 2% introductory charged on net win but they state in the future their commissions will be based on the event type and on player activity starting at 6% with discounts.
Incentives for offers: Yes, but need to contact them
Software Review: I like their software, it looks similar to BetFair and is probably the most similar to what people using exchanges are used to.
Customer Service: The times I have used their customer service I have found it fast and knowledgeable
Sports offered: Fairly limited to the major US sports with offers only available about 24 hours before the game starts.
Pricing: I found several times their moneyline pricing to better than Matchbook, but in most cases generally speaking it is higher.
Liquidity: They don't always have offers up but when they do it should be fine for most bettors that wager 500 or less at a time. Good for game day betting but nothing early or non major sports.
Other observations: Major US book backing but seems that they are not sure exactly what they are trying to do with the exchange, whether it is relying on value or stability or appearance it seems unclear.

Matchbook - Independent
Deposit methods - VC, wire, GP, Moneybookers
Deposit fees - depends on method but generally 3.5 to 4.5%
Withdrawals: By above plus check
Offers commission credits to reimburse against deposit fees
Commission: 1% to accept all offers .2% commission paid to make offers
Incentives for offers: Yes, .2%
Software Review: Their software takes a little to get used to. I don't find it intuitive but once deciphered is manageable. Does not have Betfair style look for an exchange but functions well.
Customer Service: The times I have used their customer service I have found their live chat a little slow and the chat itself seems to occasionally have problems. Friendly helpful reps with good knowledge.
Sports offered: Fairly limited to the major US sports with offers only available about 24 hours before the game starts.
Pricing: Generally speaking for major sports very competitive pricing especially for MLB and within 6 hours of gametime.
Liquidity: They don't always have offers up but when they do it should be fine for most bettors that wager 500 or less at a time. Good for game day betting but nothing early or non major sports.
Other observations: Currently the largest exchange for US players

Parlaymakers - Independent
Deposit methods - GP, Moneybookers
Deposit fees - none
Withdrawals: By above
Rewards program up to 3/4% cash back on wagers
Commission: none but net winnings are instantly paid back to GP which charges 2%
Incentives for offers: Yes, 1.5%
Software Review: For accepting wagers it is just like a normal sportsbook interface. Virtually no adjustment for regular users placing wagers. Offers are made by exchange members and basically is similar to setting lines on the back end of sportsbook software.
Customer Service: I am biased so I will leave that up to discussion
Sports offered: Huge variety, by far the most variety of any exchange, everything from major US sports to 4th tier league English soccer, props available as well
Pricing: Parlaymakers guarantees to beat any line offered by any exchange or sportsbook. So by definiton, always the best price.
Liquidity: Because Parlaymakers is a sportsbook that has an integrated exchange it always has liquidity at all times on all events with excellent limits. Early lines are available at the same time Pinnacle publishes their lines.
Other observations: Exchange has the ability to offer dynamic offers that will fluctuate with the base Parlaymakers price making the task of managing offers much easier. Also, offers can be made on all events up to the available balance thus increasing the chance offers will get accepted.

Lets discuss.