I would stay away from anything RAP4. Milsig did build some of their guns at one point but it seems the Milsig-branded ones were always better/more reliable from what I followed over on the MilsimEmpire boards. Doug Brown (creator of Tacamo before Procaps did away with his position and sold the brand to RAP4) is running Milsig USA now so you'd be in good hands customer service-wise.
I do tend to agree that I'd rather wait for the T15 if it were me but that's because I have plenty of pistols and such to hold me over until it eventually comes out. if you're looking to get into magfed in a shorter time frame, you can probably find a decent Milsig setup for relatively cheap used since a lot of people buy them, and quickly realize magfed just isn't for them and sell them off.