Face it, there is one thing that is sure when it comes to motor vehicles. All of the manufacturers produce poor performing vehicles, from time to time.
Most of the vehicles mass produced by the auto makers work and serve us well, however there are some that just don't fulfill their life expectancy. They aren't "Lemons", their are just vehicles that for some reason, either from their manufacture or from misuse, or poor maintenance, or whatever, do not make for a good used vehicle, and might not have been a good new vehicle.
I just had a bout with a 2012 Durango. Nearly a $50K truck, and I ended up returning it to the dealer with less than 500 miles on it. That doesn't make Durangos Lemons. It makes THAT ONE a lemon, though.
When buying ANY vehicle you are subject to getting a bad one, though the chances of that happening are far greater when buying used, than new. The old adage "Buyer beware" is most important when you're buying a used vehicle. Especially if there are few or no records of it's care by the previous owner.
Check EVERYTHING. Get all of the information you can, and READ IT. Ask questions, and never buy something sight unseen, unless you're looking for a project car, and the vehicle's issue (within reason) aren't a concern for you.
If you are buying a used vehicle as a daily driver. It's up to you to do the research, ask the questions, test drive the vehicle, and argue the price based on your findings.
Brand doesn't matter. You have just a good a chance of getting a bad Mopar as you do getting a bad anything else.
If the vehicle was a good vehicle from the factory, and was well maintained, and not abused by it's previous owner, there is no reason why you shouldn't expect to get good service from it, too.
On the other hand, If the vehicle was trouble prone from the factory, or was not well maintained by previous owners, or was misused or abused, there is a high probability that you will pay the price for that, and again, brand doesn't matter.
If you feel comfortable with a Toyota, then that's what you should have. Simply put, if you buy anything else, and you end up having trouble with it, you will be second guessing that purchase for as long as you own that vehicle, and longer.
Do what you are most comfortable with.