I would not recommend Nest, unless open plan house or hot air central heating. But the big question is what you get for the money. Nearly all central heating is a compromise. So looking at the TRV first. The idea is only heat a room when required, my Energenie TRV was first attempt,
also sockets, light switches, and energy monitors all on the same system, and one could use IFTTT (if this then that) to have geofencing with the TRV, it claimed to work with Nest, but in real terms didn't, and the anti hysteresis software was OTT, so to get room to 20°C at 8 am one had to set it to 22°C at 7 am then 20°C at 8 am, which means geofencing would not work.
So the far cheaper eQ-3 or terrier i30 TRV heads would do a better job to the Energenie head, I got eQ-3 bluetooth heads at £15 each, but since brexit the price has gone up.
The Drayton Wiser heads claim to have algorithms which work out how long it takes to heat the room, so can move from an eco to comfort setting far faster, but also cost more. There is also EvoHome and Tado. Hive is an odd one out, with no ability to use OpenTherm, but mainly boilers can't work with OpenTherm anyway so may not be an issue.
If looking for the best, than likely the Myson iVector fan assisted radiators are the way to go, fast response times, can heat and cool, not effected very much by furniture in front of them, and with a 5 speed fan once the room is warm can hardly hear the fan. But once you look at price, think you will look for something cheaper.
At £15 - £80 for the TRV heads, and with this house I have 18, that has to be the big cost, so step one is what do you want to spend on the TRV heads?
I call it near enough engineering, the more you pay for the heads, the easier to set up, no point getting all heads which will not work with wall thermostat, however likely you can mix, so so many are stand alone, and so many work with wall thermostat, which is more like a hub than wall thermostat.