In the under $1500 category, there are a lot bikes with imitation wheels that require constant maintenance for loose spokes. Also batteries that stop producing voltage at the first pothole due to bad welds. DD hub motors are cheap, but really drag if the battery runs out before you are home. I prefer geared hub motors.
I'm age 70, and when I quit working age 58 totally out of shape, found the many gears of a mountain bike very useful for maintaining forwards motion. I started riding a couple of blocks, and was up to a couple of miles at the end of the summer. I paid $60 for a diamondback MTB at the local Salvation Army resale, then when the axle of the first one broke with no parts obviously available, $75 for a Pacific Quantum MTB at the local flea market. Hint, don't buy the 6 speed rear axle bikes, the axle is too thin for adult weight. The 7 speed rear axle ones are a whole .370" thick.
In the new bikes for heavy people category, I've been much impressed by the mongoose envoy which is under $800.
www.mongoose.com/products/envoy It has no power. You can later add a geared hub motor on the front from ebikeling for under $400, and as much battery as you can afford - A $620 17.5 AH one gets me 30 hilly miles around here on the bike shown left, which is the same configuration as the envoy. Lunabikes, ebikeling, and california ebikes provide reliable batteries.