This review assumes that you're a casual learner with no prior knowledge.
I thought I'd try learning Croatian for an upcoming holiday, as you do, and this seemed like a good bet. Boy, was I wrong.
Coming from a number of BBC, Hugo and other language courses, this just seemed more basic and old-fashioned right away. The book is dry, to say the least, with a few sketches thrown in to lighten the mood.
My real problem was with the CDs. Basically, the individual tracks are often very long, like 8, 10, 12 minutes. This means that if you want to repeat something, you have to go all the way back to the beginning of the track and start again. After a few goes of this, you lose all will to continue. Because of this, I gave up after a couple of nights in utter exasperation. Considering that Croatian almost certainly isn't exactly familiar to the average English speaking listener, the one thing you need to do is constant, frequent repeats of phrases to become familiar with the sounds. With long tracks, this just drove me up the wall.
In summary, if you really want to learn Croatian to a reasonable standard, then this course is probably as good as you'll get, but if you're starting from scratch I would highly recommend the basic Berlitz primer first.
Update 30/07/12 - I've just started the TY German course and it's in a different league entirely - colourful, informative book and very short CD tracks, exactly what I'd expect nowadays. Clearly the Croatian course needs a serious upgrade to make it more accessible.