I bought mine from a shop for a negotiated £520. I managed to get a £30-35 gunbag for £25 and a set of £4 sling studs in the deal, but to be honest, I paid too much. I could have got the same deal from Ramsbottom's for £50 less.
Since buying it, I've only had the one opportunity so far to try it out so initial impressions are:

I shot it as a side-by-side comparison with my AA S400 (reviewed elsewhere on this site).

To be honest, I find it hard to justify the extra expense of a PCP multishot over a single-shot PCP. In target FT a multishot is generally seen as undesirable. For hunting, you should cleanly despatch with 1 shot - since the rest of the rabbits then usually leg it, it doesn't matter how many shots you have left. No, the only shooting 'discipline' I can see where multishot is an advantage is in fungunning and. clearly, you don't spend £500 on a gun for this. In fact, for £140 you can get a 'semi-auto' plinker for this purpose.
The fact is, I just wanted to try a multi-shot PCP, so why not one that has a regulator, match-quality trigger, and match-quality barrel?
First impressions are mixed. I attached a Hawke 3-9X40 scope which almost fell on a 30 yd zero. Groups from a bench rest (to eliminate shooter incompetence) were about 1/3 inch with a moderate to chewy crosswind. This was as good or better than I achieved with my (better-scoped) AA S400 on the same day. At 35 yds the pellet drop amounted to about 1/2 inch and still grouped about 1/3 inch. At this stage, comparison with a .22 becomes irrelevant (which is essentially why I bought a .177).
So much for accuracy. What about general use? Well the Superten is noticeably heavier than my S400 and would certainly make its extra mass felt when carried around the fields and woods I hunt in.
The bolt action is effectively 6-stage in that it requires a 'turn up' followed by a 'pull back' then a 'turn down' then a reversal of this procedure. The more usual bolt action of 'turn up', 'pull back', 'push forward', 'turn down' is obviously quicker, while the 2-stage 'straight-bolt' action is quicker again. The result is that, for all practical purposes, the BSA is not really much quicker to shoot - shot to shot - than my S400.
Although the BSA does have a 'quality' feel about it, I must admit I am a little concerned about how rough the bolt action feels (and I have quite a lot of experience in 'mechanics and engineering'). The bolt action does load a pellet from the magazine, but it falls a long way short of 'slick'. Certainly I'm glad I have a guarrantee and I will be watching this closely.
I was told that the cylinder, charged to 232 bar (as supplied) will provide around 150 shots in .177. So far I have shot around 60 with no loss of velocity on my chrono. Unfortunately, my charging bottle only goes up to 205 bar so this may result in a lot less shots. I may have to fork out for a 300bar bottle and sell mine on.
So far, and bear in mind I've only had one session with it, I'm happy with the Superten, but I do have reservations about the cycling action which still feels rather crude and 'graunchy'. Hopefully, this will bed in and feel as smooth as a £500+ air rifle should do.