Thermostats - Nest, Hive, other?

[AmelieV88]

I feel like a bit of a luddite for saying this but I’ve never had a thermostat. Our combi-boiler needed a service today and the gas engineer had to call out the gas network as the gas was at low pressure. Both of the engineers seemed surprised we didn’t have one, we just work off the timer on the boiler and adjust the temperature on it, along with the valves on the radiator.
I’m thinking about getting one but they seem a little pricy and not really life changing for me, maybe I’m wrong? Particularly now as we’re at home all the time. Which ones are good? Nest? Hive? Other brands? Do they require someone to install or could an amateur do it? I like to think I’m pretty handy with most things but know very little when it comes to boilers.