I assume these are two options for the FreeNAS server?
If so:
The LGA1150 build is okayish. The T CPU is wasteful, since it won't actually use less power but will limit performance. I was going to complain about the 4GB DIMMs, but if you can get them at that price, go for it.
The LGA1151 is much more dubious. That motherboard screams "not a server board" - and trust me, it does matter. You might get away with it, but there's a significant risk of having to buy a replacement board because something did not play nicely, whereas the Supermicro X10 board is very popular and well-understood around here.
That said, you can try to find an X11SSL-F or X11SSM-F at a reasonable price and end up with the best of both worlds at a slightly higher cost. An X11 board would also allow you to upgrade to 64GB of RAM in the future. The main sticking point would be the insane prices for DDR4 RAM, at the moment.
I originally wanted to use the g3220 that I have lying around my house.
However when I choose the g3220 and the x10 motherboard, there's no ram that passes the compatibility filter (on pc part picker)
I'm assuming I need unbuffered ram, but pc part picker doesn't give me any options.
I was iffy about the Asus board, but it was 60$ cheaper than the cheapest supermicro.
I did however find a used x10slm for 90$ and a used x11ssl for 120$, so the Asus is no longer the cheapest option.
With both motherboards being supermicro and the CPU power consumption being similar (30W idle for the g3220 and 17W for the celeron), I think I'll go with the ddr3 build for freenas.
I'll be able to afford 16gb ddr3 instead of 8gb of ddr4, plus the cost differential of getting 8GB sticks instead of 4, is only 20$