I drove a standup electric forklift for almost 7 years, and if you can score one of those, a Crown preferably, go that route. I wouldn't worry too much about a used one, those Crown electric ones at Sam's club can run for decades, and they can be abused the whole time and still get the job done. I don't know that much about the propane sitdown models, they could be as reliable and durable as the ones I ran.
As many new forklifts as we got over the years and new club buildouts, there has to be a few used ones on the market. I never knew what management did with the older forklifts but every once in a while we'd get a few new ones and one or two of the old ones just disappeared, but they still ran fine. The batteries are crazy heavy, but the way you need to use it you can just charge the battery while it's in the forklift and won't have to worry about getting the battery changing system.
On a side note, one morning a guy forgot to put the plate that holds the battery in the lift back in, and when he turned the corner while leaving the battery changout area the battery rolled out of the lift and went through the receiving office wall. It left this cartoon-like perfectly square hole in the wall like the coyote would when he'd run through a wall. It took us a few hours to fix that mess, and the guy lost his job because he didn't do so well on his test, his drug test, the one they'd give you if/when you screwed something up. If there would have been someone on the other side of that wall I can't imagine what it would have done to them. Maybe they just get knocked down, or maybe that 3K pound battery smashes them up badly, but thank God nobody was hurt that day.
I've got a few dozen good forklift disaster stories from my years in big box retail. I never had a bad accident while driving, because I was the best operator there ever was
, but I did have a pallet of Dixie cups buckle while I was lifting the pallet because someone put a pallet on top of the cups that was too heavy to be on top (pallet of clothes washing detergent in the 5 gal buckets). We had to downstack both pallets from the top rack but we couldn't just climb up there ninja style, we had to wear the safety equipment harnesses and strap ourselves into the lift cage or the steel we were climbing on. It took almost as long to get the ok with all the safety stuff as it did fixing the problem. SAFETY FIRST!!!!