Hello,
I've got the Arena, (with the TS300 sub), and I've found it to be great.
I demo'd it against several speaker sets including the KEF 3005SE and 5005, and the B&W MT-30, (don't forget they were around at the same time as the Arena but just haven't gone down in price. In fact in the same group test that the MT-30 got 5 stars, so did the Arena).
For me the Arena was head and shoulders above all the other speakers I demo'd. It had much more clarity and detail than the others, (run close by the KEF 5005s), had the best top end, (the 3005SE was maybe on a par if a bit brasher, but the MT-30s were poor in this area, for both films and music). It was also more musical than any of the other sets, (the B&Ws ran it close here if it wasn't for their problems at high frequency, and the 5005s got somewhere near when paired with the PV1 sub from the MT-30). I didn't detect any weakness in the sub in comparison to the PV1.
All in the Arena was the only speaker set that I thought was good for both films and music, and the only one that I thought gave a cinema sound with films rather than just surround sound.
What I also think's good about it is that there are other dual concentric speakers from the rest of the Tannoy range, not least the Highline 300 and 500, that could be added in later to grow it and keep a similar sound, and look if needed.
These are just my opinions, but I did take a couple of people with me, and have a few different demos. There are also other packages like the Arcam Muso / Logo and Monitor Audios I didn't demo the Arena against.
Hope this helps. I have got the Arena, but I'm not biased as such. I started wanting something else, but the Arena sounded the best.