Also Lattice only does LUT4. (Their internal look up tables have 4 inputs) The Artix-7 has LUT6. From what i heard that means you need more than 1.6 times more LUT4 than LUT6. Not including the fact that Artix-7 includes other hardware features which are sometimes wired in to a desgin

Note that you can't easily compare LUT count between vendors or even among a vendors different architectures.

In any case, I think ecp5 is partially supported by open source tools which should make it much more interesting to hobbyists.

I haven't played with mine yet, but there's an open toolchain for the ECP5 :)