I have only used the DM5 stereo microscope at the current time, we're starting up a beginner's microscopy group run by an ex 'professional' microscopist, though not on bees, after easter, so I've yet to really try out the SP20 in anger so this really is a beginner's assessment:

The stereo microscope is certainly easy to use. Grab a bee (dead preferably or they tend to run/fly off) and put it under the scope and have a look at it.

Both come nicely packaged so there's little chance of damage in transit, both come with dust covers and seem to be well put together and solid bits of kit.

There is little in the way of operating instructions that come with the microscopes though there was a suggestion that I should have some oil for the compound 'scope which I don't seem to have and Brunel's site is pretty weak on that side of things in terms of figuring out what other bits and bobs a budding microscopist might want or need to get started and/or take it to the next level.

I did find some better images of the two 'scopes:





From my limited experience point of view, what I like about the stereo 'scope is that it takes batteries so you could chuck it in a bag and take it with you to the apiary and have a look at things while you were there.

My complaint with the compound is that the lead for the light is very short. Remembering way back when to science lessons in school, it'd be fine when you have a plug a foot or so away next to the gas tap, but for the rest of us where the sockets are a few feet a away from the table and on the floor it's not that practical.

Otherwise they both seem to be well put together and solid bits of kit, especially considering you can have them both for a shade over £100.

My gut feeling is that if I get into the microscopy side of things at all that I will quickly find myself outgrowing them, certainly, the compound one and wanting to get something better or more flexible relatively soon. I'd like to be able to put a camera down it without having to remove the eyepiece for example.

Once I get a chance to use them properly in anger I'll update my thoughts.