I owned a 1/5th share in an Apache from 1991 to 1997. It was a 1956 model with the 150hp O-320's. There was plenty of power in those engines. It is true that if you load up the Apache to max gross, or even something a little less that you won't be able to hold altitude, but with 80 gallons of fuel and two people it will maintain at least 3,000 feet.
My take on the engine out performance is this...If you lose an engine, you need to get down and land. Having the other engine operating will increase your glide and decrease your rate of descent as compared to a single-engine airplane. Do you currently fly any singles at all? What is the engine out performance in those? What altitude are you able to hold in a single with an engine failure?
As far as the weight capacity...I have taken off with 4 adults in the plane on a 70 degree day from South Lake Tahoe airport (elevation about 6300'). Not the greatest performer, but it sure did the job.
After I sold my share in the plane, I figured out how much it actually cost me to operate over the years I owned it. It came out to just over $55/hr (this was when gas was, at most, $2.15/gal). Doing pattern work I had the burn at 5.7gph/side. On longer flights it was more like 7.1gph/side.
The interior is roomy. The backseat took about 1 minute to remove if more cargo room was needed. If need be you could even sleep in the plane with the backseat removed.
I was very happy with the airplane overall. I had a good group of partners who all helped out to work on the plane to keep the maintenance costs down. If you've never owned an airplane before, consider what your time is worth. Would it be better to save a little money and have an airplane that could be down for weeks, or to pay the extra money to rent an airplane?
For me, it was better to own. Not only did I learn a lot about the mechanics and systems of the aircraft, but I built up those ever-important multi-engine hours that helped me gain meaningful employment as a pilot.
Good luck in your decision.
Cheers!
GP