Bulky, heavy!
But nonetheless they are built solidly and you very rarely hear of them failing electrically. I seem to recall a few reports of waste/fresh tanks leaking but they can be patched up as it is a fibreglass construction (careful of abuse, will crack if anything whacked into it with force). Alltec engineers are very good at their jobs, but the service can be a little ropey if they're busy (never get the call backs you're promised etc etc... maybe they should charge all their porty users £50 a year for support

).
Vac motors configured in parallel unless I'm mistaken, so good on airflow but lacking lift. Depends on your views as to whether this is preferable to an in-series config or not!
I've used a similar machine and the heater was a piddly little thing that took AGES to heat up, the element is much smaller than a ninja which heats very quickly in comparison