I've had better experience with refurbished devices than new. When you order them new you are likely to encounter the array of problems you read about online. Buying refurbished means they took it back, fixed the major issue and sent it back to you.
If it's a true manufacturer refurbished tablet, you should be fine. With Samsung, the serial will start with 'RF' to indicate it's a refurbished, and ONLY Samsung-refurbished units will have the new serial number.
I have a Galaxy Note 10.1 (2014) that was factory-refurbished, it's been working great so far.
Deoends on where you buy it from. Refurbs are not a bad thing IMO as long as you buy it from a normal OEM or reputable store front. This is not to take way from sites like swappa (And I love them!) but I'm talking about if you are worried. You just gotta do some research with whom ever your buying from.