They are nice. They create a different rhythm in a house, because (assuming all systems are similar) you fire them up for the winter and leave them at a constant temperature. So you’re not adjusting the thermostat for when you leave the house (unless maybe you’re traveling). You also don’t have air blowing around like you normally would, so if you need to circulate air, your mechanism for that will be different. If your area is particularly cold or if you want a particularly warm room, you can also double up on the hosing in an area. Oh, and your thermostats will control zones, so you can set some zones higher or lower than others.
This probably doesn’t apply, but when my gf purchased her house, the inspector did not catch the problems with our radiant heat, which was uneven. When we finally had it looked at, it turned out the valves that control flow to various zones were broken. What I think happened is the fuck-up who installed the valves broke them when he installed them and then just tucked the problem into the wall. So we got the upstairs fixed at considerable cost and that triggered a problem where the downstairs valves would not shut off and made the downstairs unbearably hot. Once we got both fixed, things were fine.
Others may chime in to the contrary, but there can be a trade off in climates where you might have warm days in winter, because the system doesn’t respond as quickly to thermostat changes. It’s like a 24h thing to get to the desired temperature instead of more immediate.