I dive a KISS.
The one thing you can't say about an inspo is that it's neat and tidy. The inspo is the drunk kebab of the rebreather world - it does a job very well, but it isn't pretty, and sometimes it goes wrong.
But most of the time you'll survive it.
The KISS is depth limited which is my problem at the moment, I don't want to put in hours and hours of work on a unit which I'm going to have to change for big dives (that said 100m isn't just big, it's pretty massive, at least for me!) and requires the diver to pay attention to it during the dive more than any other unit I know of. If you can live with this it is very well made and despite my buggering about with it it's only been broken once, and that was by me! Parts incoming...
Personally if I was buying right now I would buy a Meg. No question. THey are like an inspo but well built, do what they're supposed to, and don't weigh 3 tons for flying them around.
If you're not planning to dive it out of driving range (which lets face it very few of us are) then the Boris would be my next choice.
Next on the list would be the mid-range breathers, the kind of thing most of us dive, largely because many of these designs either weren't out when we bought them or because they're not old enough to have much of a secondhand market. This is the Inspo and the KISS.
Other options available to you - Prism (not seen one yet but they seem to be popular in the states, and it probably won't be too long before we see some over here - but I wouldn't volunteer to be the first one to get one), An old MK15 (vintage choice, and more trouble than it's worth IMO, just get a Boris, same cost and UK support)
I think that's covered most of them. It's a decision only you can take really. You know what you want it for, and you know where your diving's going.
If you want to have a good look at the KISS I can take i down to Cornwall with me at the start of October, I'm free Monday to Friday, if there's somewhere you know of which is easy to get in and very shallow you could probably dive it (obviously on the understanding if you die it was nothign to do with me, and I'll abandon your corpse to prevent ending up in court!). PM me if you're about.
Digs.