Is getting a phone a couple years old worth it?

Not familiar with those models. But I always get used phones.

I still have a oneplus one and im fine with it

Are you talking refurbished or used from somewhere like Swappa? I got a refurbished S5 Active about 8 months ago and it works perfectly.

It depends on what you want to do with the phone. For most people something like a $60 BLU R1 HD is all they need. It comes with Marshmellow not Nougat but it's pretty much stock and runs very well for such a cheap phone. Also I think you can runs custom roms on it if you want. If you're an Android user I think it's insane to pay more than $400 for a phone. A lot of manufacturers are making phones with flagship specs at $400 or less. The lack of updates worries some people but that's what you have to deal with if you use a non Nexus/Pixel phone. I use an iPhone 6 plus and I used to upgrade every year. I stopped 2 years ago because I could no longer justify the cost. My 2+ year old phone works perfectly fine.

The S5 is probably the worst phone ever made. S6 is world's better. Having said that I'd only get a model that is one year old.

My S6 battery life is terrible. Atrocious. Next phone I get, battery will be #1 deciding factor.

I've had my iphone 6 for more than 2 years now and have no plans of replacing it anytime soon. Still works great.

I am still rocking an S4 because I don't want a huge phone like all of the new ones are. Mine has a custom rom on it though

I have an S6 Active and I think it is a great phone. I usually use iPhone and have for many years. Bought this phone from a friend while my iPhone was down and I am runnjng two phone now for work purposes. I think the S6 would be great in your situation.