I've been living and working in Barcelona for almost four years now, and from the very start, I felt fairly confident of my Spanish. Of course, it wasn't the only thing I used, but it formed a strong base for me in vocabulary and "ear". Later, when I had more time to study Spanish grammer, things fell into place much more easily for me. For the price, it really was a pretty good bet. I realize some folks with a more academic background might bristle at the thought of repeating phrases to learn them, but my actual experience was that this served me quite well.
My only problem with the tapes was that they were recorded in American Spanish (that is, Mexican vs. Spanish). It took me a while to work the edges off of my pronunciation when I got to Spain (for example, I pronounced "Hace calor" like "A-sey calor" instead of "A-they calor"). This is not a big deal for most, though. I wish they had produced a Spanish Spanish version, but the market for that sort of thing must be quite small.