I have a1997 maxima, it takes 45 minutes to remove the alternator and replace it, i've done it before. Apparently you have to disassemble the entire bottom right of the car to get it in the opinion of one shop tech over the phone.
Now that i have it replaced (by myself) I see it took me about an hour and a half (my first time doing this repair) and all i had to do is remove the idler tension pulley, remove the 4 bolts holding on the AC compressor and swing it out of the way, and what do you know, i have the job done, all while laying on my back in the school parking lot in the snow.
If you want to torch your wallet to smithereins, go to japanese auto works.
otherwise learn to work on your car yourself. or go elsewhere.
Pros: reccommended as very friendly shop
Cons: turns out they are just the same as everyone