Hmmm...I can't say that I have ever used a gown like that or even plan to in the future. I personally didn't have a problem with the hospital gowns and felt that they covered enough for me (If I remember correctly they wrapped around your back and tied at your side). I think Pretty Pushers definitely put a lot of thought in the design of their gown with all of their opening and reasoning behind them but I would feel more exposed in that than the regular hospital gown.Although by the time I got to the hospital after laboring at home for a while, I was ready for that epidural and you can't get out of bed once they put the line in so gown type didn't really matter at that point.
I did have one friend who was given a gown as a shower gift (though I don't remember the name of the company) and she wasn't really keen on using it because 1) it was black and white paisley design and felt that she would look like a cow and 2) didn't get the whole "designer gown" concept since the likelihood of it getting ruined from blood, etc during the actual pushing was high.
Honestly though, when it comes down to it. it's whatever you think YOU will feel comfortable in. If think you will feel batter and more comfortable with a Pretty Pusher or other gown like it, go for it. Good Luck!