Seeing lots of Gigaclear comments which are inconsistent. Here's what We've found.
Yes: Installation was quick and efficient. (once the service was available.)
Yes: cable is just below the grass level in the garden. (worrying)
No: It's not always fast. (but this is complicated. Keep reading)
Yes: they use CGNAT which shares IP addresses.
No: They don't use IP6 (which would improve service.)
Yes: The use a LOT of caching. (Trick to make service look faster and reduce server load)
Yes: The Linksys wireless is below average. (And it sends out a hidden SSID which can't be switched off)
Yes: They somehow NEED CDN services. Some pages just won't load without it.
Yes: wireless is good if you're in the same room or room above.

Tech support do seem to respond, but don't volunteer much in the way of technical information. General impression is support dept are over taxed.
Overall found to be a good value service so far, but with some significant flaws to work out over time.
I give it four/five at present.