If you can afford it, then I'd go for it... there are I believe 11 different Penthouse suites, all with varying different layouts and views and different types of balconies depending on which block/building you get.
The difference in price between rooms at CSS is minimal. The Penthouse is the best deal IMHO. Just for the heck of it, I checked out the cost for June 2011 on the web site for the TA I use. The least expensive room is a Deluxe Ocean. The difference in price between that and a Penthouse is $140 for 7 nights. That's $20 more a night. The difference between a Beachfront Suite for 7 nights is $64 or $9 a night.
Go for the Penthouse, it's your honeymoon!