I will note that since the above was posted, a few more clones became available, then went off the market, and moreover, we have introduced our own Carbide Compact Router in two versions:
As regards which should be used — the typical reasons folks get an ER-11 unit are:
compatibility w/ a Nomad or other CNC which has an ER-11 collet
use of endmills in diameters other than the 1/8" and 1/4" which we provide precision collets for (but note that additional sizes are available from Elaire Corp.)
need a collet system which draws the collet out as the nut is removed — note that this shouldn’t be an issue, and the collet in the standard should not get stuck — if it does, contact support@carbide3d.com