Don't have one, never used one, but. From the advertisement, it's an indoor CB/11 meter antenna. Any indoor antenna isn't going to be the most 'thrilling' in the world. But if it's made sort of close to what's required for an 11 meter dipole, it shouldn't be all that bad. You should be able to make one for about the same price (or cheaper after figuring in shipping costs). I see no reason that the 'BS-1' would be any 'better' than a home-made one. It would require some sort of basic building skills though (reading a yardstick, soldering, etc.).
Being naturally 'cheap', I just can't 'see' buying a dipole rather than making one. That's me, though.
- 'Doc