What do you guys think about them.

I found an old 1979 built one a few miles down the road from me. All original, no mods that I can tell. It powers on, HV goes to 2200 on CW and 2800 on SSB.

The HAM that has it says it was his friends amp that went SK 4 years ago, and the guy had recently replaced the tubes before he died. It has been sitting since then. HAM selling it says he put 95 watts into it and an external power meter should 1000 watts output, but he also said the HV was 1000 and the Plate current was 2 amps when he made a good contact on 80 meters with it and the watt meter showed 1000 watts. He was looking at the 2 on the scale and thought it was 2 amps when it was really 0.2 amps.  No matter how you slice the math that means 200 watts so that makes no sense. He doesn't know how to tune it and didn't even try.

Is this amp worth the $700 he wants for it?

An operational SB220, even if it needs some work is well worth $700.

IMO $700 would be fine if he could show a full KW out. Expect to change the filter caps/rectifiers at a minimum and it should also have the
Harbach mods installed.

How much experience do you have working on amplifiers? Do you have tools and testing/measuring equipment? Are you good at soldering?
I would advise to pass on the amp unless you feel comfortable working on it. Even then, I would make sure everything is in excellent shape and works as it should. If the amp needs work I would not pay more than $300.
Most likely PS caps need to be replaced. Tubes are questionable too. How do the tubes look? Any sign of overheating? Just the fact that the owner does not know how to tune it, tell me that the tubes may have been "cooked". This is not a fool-proof amp. Keep that in mind. Sooner or later it will require some work. It's an old amp.

My advise would be to either spend the money on a newer AL-811H amp or get a used Ameritron ALS-600 for about $700. ALS-600 is a simple transistor amp that requires no tuning. It's easy to use and will put out about 500 Watts. The difference between 500 and 800 Watts will hardly be noticeable on the receiving end.
Another great choice would be a used AL-80b in excellent shape. They sell used for around $700, in great shape.  It uses a tough,  single 3-500Z tube and will put out about a kilowatt.

Never worked on an amp before but I have a EE degree so I understand the basic concepts and necessary precautions.

There was a used AL-80b locally, guy wanted $950 for it. I think I will end up buying a new AL-811H from HRO and not max it out

Thanks fro the advice

Love my SB-230. But it cant do 160m.

I was just given an SB-200 so paying a couple hundred $ to do the harbach mods was no big deal....learned alot and had alot of help.