Is the Trek 820 a good moutain bike for road and trail use?

I recently visited a bike shop and looked at a Trek 820. I like to run (20+ miles a week) but I injured my knee about a year ago, so I can not run as much as I used to. I am looking for something that will give me a workout. Something that I can use on roads primarily, but every so often on trails. I was quoted a price of $250 for the Trek 820. Is this a good deal and is it a good bike?

It is fine for onroad and on groomed trails... no logs, no boulders, no jumping.

$250 is not a bad price, but you can get a comparable bike from KHS (Alite) or Diamondback (Outlook) or Raleigh (Mojave 2.0) for about $40 less.

Thats a good price for an entry-level bike. I rode one for many, many moons and put about 10k miles on it. I put some Bontrager Comfort B tires on it; smoothe center tread for trails/pavement and some shoulder knobs for off-road. Since the frame is steel, it rides nice on the pavement, but is a bit heavy compared to other bikes.

for that price ask for lifetime maintenance from the shop and i think you got the best deal possible. treks are very good and reliable bikes, plus is much better on your joints, after riding some time, you might be able to go back to running

Not a bad entry level / casual bike. Have anyone told you that the best way to recover from leg injury is bike riding and swimming?