BuckeyeBlast, as long as the P89 fits your friend properly, it should be an excellent gun for what he wants to do. I have one I bought not long after they came out and it is excellent.
I don't have a lot of rounds through mine (around 2000), but what I have shot has been uniformly outstanding. Not the most accurate gun I've ever shot, but the thing is a TANK! It is what it is- a full-sized, duty-type gun. As such, it is not real suitable for most people for CCW, but for a range or house gun, the size means it is very shootable.
Due to it's over-engineered construction, it should last for decades, even if shot constantly. While I have read about P89s that have been damaged by outside forces, I don't think I have ever read of one that wore out or blew up. In fact, one of the tests when Ruger developed the gun was to thread a plug into the barrel, then shoot a round. IIRC, the extractor blew off, was replaced and the gun went on to shoot several thousand rounds with no excessive wear or other problems. They also took another P89 and milled off all of the slide below the ejection port and shot the crap out of it. After several thousand rounds, no dimensional changes and no excessive wear.
The trigger is not the best of any auto I have ever shot but it is usable. As the gun is used, the trigger does get better but, even then, it is not stellar but it is OK for what it is. The gun also has some sharp edges but, if you can detail strip the gun and are handy, this really isn't a problem. Even as it comes from the factory, it isn't a real big problem, just uncomfortable after a long range session.
Factory magazines are great, as are MecGar brand aftermarket mags. MecGar also makes a great flush-fit 17 rd mag. Stay away from other aftermarket mags. My P89 turned into a jam-a-matic with ProMags and I have read that other brands don't work too well, either.
The only real problem (if you like accessorizing your guns anyway, I don't so it doesn't really matter to me) is a distinct lack of aftermarket accessories for the P89. Sights and replacement stocks are available, as are holsters, but that's about it. The P89 isn't a good gun to get to turn into a race gun, but I honestly think that it's best left in it's factory form.
Overall, as long as the gun fits your friend, the P89 is a great option. Durable, reliable, accurate enough and hell-for-stout. Should work out very well for him if he decides to get it. I use mine for my nightstand gun, so that ought to tell you my opinion of my P89. If it wasn't reliable and accurate enough to stake your life on, I wouldn't be using it.