keep hr20-700 or try to get hr24?

I currently have 2 hr 20's in the house, one in living room and one in my bedroom. my kids have i believe hr21 and hr 22, we are all networked together with direct internet and whole home sharing. My hr 20's both seem slow sometimes, but they do work. I was promised an hr24 for free when i called them, and of course, they lied, i got an hr 21 mailed to me, so i called and told them to pick it up. they set up a service appt for the person to bring an hr 24 hopefully to me directly-if they have them on the truck-but now im thinking, should i just keep my hr 20-700 i was going to swap out in our living room, or go for the hr 24? I am not in any contract right now, been with them for 16 years, if i get it, i go into a 2 year contract, not a big deal, but there customer service the last few years has been terrible.

is there a huge advantage to getting the hr24 and can i just plug my internet wire into it to continue with whole home dvr service?

thanks!