While I haven’t done extensive testing on these, I have some experience with 3D printing pens. Overall, I’d recommend against them for use in a makerspace with a limited budget. They’re generally inexpensive, but have such limited utility and reliability, I don’t think they’re worth the shelf or budget space.
I’ve used a 3Doodler 3D printing pen at a makerspace and I bought a cheapie one off Amazon. I though the 3Doodler was okay, but found it too slow and manual to make anything very interesting to me. 1
Given the speed, lack of precision, need for a steady hand, market packed with cheap knockoffs, there aren’t a lot of these tools I’d ever use. The highest personal use for one of these low speed, low volume 3D printer pens I could think of would be repairs of 3D prints. For a school or makerspace, these would be interesting, but even the best ones would probably be more novelty than any kind of real tool.
The one exception would be Tim Keller’s Struder which I’ve seen and used. It essentially uses a full sized extruder and hot end and has the kind of flowrate you’d expect from a 3D printer, except that it is hand held. The artists who’ve used his Struder have made some pretty cool things.
Making a Makerspace