There are going to be so many opinions here, unfortunately, each site has different requirements and what may work well for one site may not be so good for another.
For me, I run two Motorola GR1225 repeaters. The nice part is that these repeaters are plug and play ready for network interfacing, so if you aren't too good with building custom connectors or soldering, this may be a better option. The 1225 is 100% continuous as long as you run it on low power (25W) which is reasonable enough. (Personally I have seen little difference in range between 25W and 45W.) Purchasing a Rim-Lite with the 16 pin motorola plug, you just plug in to the back of the radio, plug into the pi, adjust your audio in/out and your all set.
You'll definitely want a good BP/BR duplexer. I started off with a flat pack but after switching, I cant see myself using flatpacks outside of mobile repeaters ever again
For feedline, I use LMR600. I live in a salt air environment being less than a mile from the ocean and bay and never had issues. Others have said they had issues with water getting into the feedline and corroding the jacket and core however I believe this is because those persons were using junk LMR. I go to https://mpddigital.us/ for mine, nice part is they have a lifetime warranty, so if anything happens to the coax short of a lightning strike, they will repair it without question. If you are building it in a high RF area or a very long run of coax, you may want to consider 1/2" -1" heliax.
For an antenna, I use a Comet CA-712EFC which is a high gain omni-directional antenna. It seems to work fine for me.
