Hi Veji,
I am a big fan of the FFG mats as well as the third party mats that BG has available for us to use. I feel that the "slip" factor is not a real problem for me, however I have seen that complaint in the past.
Most folks that found this to be an issue have remedied this by getting some weight on the bases of their ships. This can be tricky, but a metal washer can fit in the underside of the base to add some weight.
Another thing to keep in mind is the FFG Tourney Rules, which have some requirements related to the playfield.