I have hands-on experience with the Pasadena/Pasadena Plus set.
I found them to be rich sounding and expressive pickups with clear sounding harmonics. They "feel" like a high quality pickup set and manage to maintain a vintage-hot feel with higher actual output. I do wish they had a little bigger/fuller top end and a tighter feeling bottom end, but that's just personal preference.
Their voicing is slightly scooped...fairly bass-heavy with a balanced midrange and a small hump in the upper mids, especially on the bridge model. To me, the heavy bottom end can start to feel a bit "flabby" or "loose", especially if you down-tune at all. Also, the neck pickup is voiced on the warmer side, so it gets a little dark sounding for my own tastes.
They are fairly "open" sounding, but manage to feel a bit restrained up top in a way I can't really describe. Some people will really like that, though, as it keeps the pickups from being piercingly bright at all.
I think the closest pickup in the Seymour Duncan lineup to the Pasadena Plus bridge would be the "Custom 5", although I'd almost suggest these were half-way between the Custom 5 an "underwound" JB. They definitely don't sound quite like anything else. The neck most closely resembles Duncan's '59 model.
BTW...I can't imagine what the regular "Pasadena" bridge model would be like, since it is an underwound version of the "Pasadena Plus". My guess is that the regular "Pasadena" bridge model further exaggerates the "scooped" qualities of the Pasadena Plus bridge pickup. Again, some might like that, but I wouldn't want these any more scooped than they are.
Some of these characteristics will change with the guitar and the amp used. However, whether or not you'll like them ultimately depends on what you're after tonally.
I don't want to scare you away from them, they are great pickups. Definitely a versatile classic/hard rock/metal set with the high quality feel of custom shop pickups.
If you can get them from your friend for close to the price of DiMarzios/Seymour Duncans, I say give them a try!