Having gone through a number of ISP's over the past 15 years or so, I find that UNO are consistently reliable. Excellent service throughout.
I agree - Uno & Matt (and indeed Xilo) have been excellent and I've a few accounts for various reasons through them. They've been responsive, accurate and talk to me at the right level given I don't need handholding.
Plusnet are owned by BT and as such I would take what Plusnet say 'with a pinch of salt'.
...whereas my experience of PlusNet... well that's not so good. A direct "retail" account is often unreliable, and even though it now sync's at 6700 odd down and 2500 odd up (yes, Annex M), and clearly the downstream figure is broken, PlusNet refuse to escalate to BTW to get this fixed - despite me telling them exactly what to do, since I do it daily.
Meanwhile as "PlusNet partners", our experience lasted 2 weeks, and I moved the 3 lines that we'd migrated in as a test back out, because they're the most incompetent bunch of morons I've ever experienced & they lie - for example, they told me that to allocate a single public IPv4, they HAD to have a full network diagram, a full Ripe form and so on - which is cobblers, and despite eventually admitting there is no such requirement (I do this every day), they refused to provide a static.
It turned out a few weeks later the reason for the refusal and intentional delay was because they had none and were waiting for BT to give them some. There are threads about this elsewhere. They're full of bull and are hopeless.
Sorry you can't tell the difference between a trustworthy ISP and one that can hide behind live chat and lies.