I laid both our kitchen floor and bathroom floor without any previous experience, though I did a lot of research befroehand and am fairly practical on the DIY front.
The kitchen floor was a piece of cake, using 300 x 300 ceramic tiles. The bathroom, using 600 x 600 porcelain tiles, was an absolute nightmare, and hand me cursing for weeks, though the final finish on both jobs is pretty much perfect.
The difference is that porcelain tiles (especially the 10mm thick floor ones) require a dedicated wet disc cutter, you can't just score and snap them like ceramics as they are hard as nails. Also, bear in mind that using black or dark grout (which I presume you'd want to with black tiles) gets absolutely everywhere, though at least will be easier to clean/polish off high gloss tiles (which mine weren't...)
I think any gloss black tiles eventually dull as they are slowly covered in a fine network of scratches from everyday use, just like the cobweb style swirl marks on a never-polished black car.