If you have the 1900acs, then you want to install "shelby" image.
If you have version 1 (v1) then install "mamba" image.
If you have version 2 (v2) then install "cobra" image.
I'm not sure if trunk now includes the "nand" patch or not, but if you have problems rebooting, just post to the 1900ac forum, and I'll send you to a link for a image that does include the nand patch.
Actually, I have found trunk to be very stable, and haven't heard of anyone's router crashing. However! I always have to make the statement that your experience may differ. However, with good communication with this forum a lot of newbie issues can be resolved fairly quickly.
P.S. If you haven't done ANY research about OpenWrt, and you install trunk, you're not going to get a web front end. You have to SSH and install LuCi (#opkg update ; opkg install luci) << example to get a web front end.
If you don't know anything about ssh or Linux, I recommend you do a lot of reading first.
It doesn't appear that Kaloz images have been updated since the 27th of November -- Recommend for the latest updates (New wifi drivers etcl) that you go with trunk.
You are welcome to install my image build (David's) which does include the latest wifi drivers and nand patch for acs. The kernel is 4.1.13.
(Last edited by davidc502 on 2 Jan 2016, 19:45)