This is a very interesting question and i think the answer is generally yes. These days power meters are pretty accurate, but they all have their limitations and there are situations where accuracy can be off. Also, even some big name manufacturers have put out bad power meters over the years, and there’s always the chance that you might get a lemon, but with some research you should be able to avoid the former problem and I would expect the company to help you correct the latter.
It’s not just the bike, it’s also the capabilities of the power meter and making sure you can get what you want. For example, a power meter that measures at the hub (like PowerTap) will read lower than a powermeter that measures at the crank or the pedal, and that’s normal. It’ll read even lower as the drivetrain wears and there is more resistance in the system, and that’s normal too. So, it will measure differently, but that’s okay.
Similarly, a left-only or right-only power meter will measure differently (and potentially not be accurate) if you have balance issues, because their algorithm essentially measures on one side and doubles it, on the assumption that everyone’s balance is 50/50. If you’re 46/54, this will have a bigger impact on the wattage / accuracy the device returns. And your balance might be different at different wattage ranges: for example, my balance is pretty much 50/50 all the way up to roughly FTP, but after that, especially once i’m fatigued, balance goes out the window. Whenever i am using the cheap single-sided PM i picked up on ebay, i take values towards the end of the workout with a grain of salt and try to keep in mind they might be low.
Not necessarily a problem, just something to keep in mind.
One of the best resources for reviews on ALL gadgets, basically, is this guy called DCRainmaker who runs a blog and does reviews. It’s really great stuff. Maybe start with the 2018 Power Meter Buyer’s guide. I think you will find there is no one “best” choice, just the one that is right for you.