I've only just started to play around with IPTV so as such have little frame of reference. Therefore I'm not going to give any X/10 ratings, instead just make some comments about my experience that might be useful for others.

Beast TV

After a fair bit of reading, it seemed like Beast was a favourite for many at the moment and seeing as it had a great selection of UK channels and sports it had what I wanted. Went through https://my.ip2box.com/ which had a simple checkout process and I received my login details in around 30 minutes, paid $15 for a month.

Running via the Beast APK on an Amazon Firestick 4k the live channels ran much better than I expected. I only checked the UK ones but the quality was decent (couldn't tell the difference on my 50" compared to usual HD TV channels) and while they sometimes take ~5 seconds to load up I never noticed any buffering or sound issues (on a 220Mb line). As for VoD I was disappointed they didn't have anything (currently being rebuilt I believe) so if that's a priority for you then do consider it, however, for me, it wasn't a concern. Overall for my first IPTV experience, it has been working great and looking forward to watching the football tonight!

Plex Share

As Beast came with no VoD I decided to pick up a Plex share also through https://my.ip2box.com/ for $10 for a month. This took a few hours to come through (likely as a bit more setup) and I was blown away by the amount of content and quality. Running through the Plex addon for Kodi (which they recommend using over the Plex APK, why is that?) playback is very smooth and the few times that there has been a small amount of buffering (usually just when I start) a quick pause for a few seconds to give it a head start solves that. Huge selection of films (seems to only do rips, no telesync so nothing of low quality there) and TV shows and everything imported into the Plex addon so they are nicely indexed. Overall very happy with this so far and assuming it stays up and the content keeps being updated I'll likely be using it for a while.