Guillotine cuts are not sharp.I have never used a flooring guillotine. That particular model (and style of model) does have some pretty poor reviews with regards to the quality of cut though.
To be fair, it is at least six times cheaper than trade model though.
They go under the skirting, but it saves time and dust, especially if you're working in a flat and have to cut indoors.
For clean cuts see above solutions.