Rental, fleet, single owner used, dealer demo, or new... it's all about the value you put on it. When I purchased my prior vehicle (2008 Acura MDX) it was the dealer service loaner and was 12 months old with just under 12k miles. So basically a rental. I saved ~20% off the 2009 invoice price, plus didn't pay the new vehicle destination charge, and they CPO-extended the 4/50k warranty to 5/70k. Allstate considered the vehicle new, as did the bank who gave me the loan. I was pleased that I paid $35k for a ~$43k vehicle, but someone else might feel the value of buying brand new and knowing the condition of their vehicle since day 1 is worth that 20%.
I sold the Acura when I bought my LC in Jan 2016, but in 7 years and +65k miles (10-15k of it towing a trailer that was really too heavy for the vehicle) all the issues I had were electronic (Nav DVD player died, bluetooth receiver died, bad A/C relay, bad VSC sensor, etc). I have no doubt that "rental" (former loaner) will mechanically run 200k miles without significant issues. Modern vehicles, particularly those from companies like Toyota and Honda who are known for reliable, high mileage vehicles, can take a lot of abuse. That's not to say someone jumping that Acura over speed bumps at 50mph couldn't cause suspension damage, but if the vehicle inspects OK at purchase time I wouldn't be too concerned about "hidden" problems.
As with any used vehicle you want to get a reputable mechanic to do a thorough inspection. If it's truly a fleet vehicle (or a rental) it's effectively a multi-owner vehicle - the question is just whether "multi" means "one or two" or "hundreds". A single prior owner could have beat the crap out of it on a daily basis, it's just that statistically if you put hundreds of people in the vehicle someone probably abused it while they drove it. Then again if they did abuse it, it's probably a small number of miles, versus the single owner who drove however they drove for thousands of miles.
BTW with 4 months of warranty left, if this is at a Toyota dealer I would ask them to include the 7/100k Platinum VSA. It's under $1300 (despite how much they may try to sell it to you for in the finance office). And if it's not because it's still under warranty you can go to any dealer in your state and purchase the VSA from them (though you won't be able to finance it into the cost).
