I recently picked up a Radical Firearms 6.5 Grendel. The thing shoots great, but the trigger is less-than-stellar. What's the best, reasonably priced replacement trigger that doesn't take a NASA engineer to put in?

CMC is a very nice trigger and takes less than 5 min to install. Price is around 170.

X2!!

I've used CMC and Timney. Both are good CMC a little better priced.

Installed a POF trigger in my last build and have been very happy with it:

https://pof-usa.com/product-category/upgrades-accessories/triggers/

I'm an idiot and installed a CMC drop in trigger in about 15 minutes. Went from 7-8 lbs to 3.5.

Geiselle beats all those listed so far

CMC

Yup. Geissele SSA-E, or SD-E if you want a flat trigger.

I just installed a Geissele SSA-E in an AR-10, it's a really nice trigger. If it's in your budget, it would be the first one I recommend.

For the money, I would get a rock river over the CMC. IMO the CMC is not worth $50-80 more than the RRA.

If you can wait for them to build one, I've heard the LaRue MBT triggers are very good as well.

Ordered a CMC. Watched a few YouTube videos. Looks like you have to remove the handgrip?

I use POF triggers and have been very happy.

What do you think about RRA triggers?

CMC is alright. Rise is nice. Quite a few drop-ins available.
Geissele is nice but it's not a drop-in trigger if that is what you want. I have two Geissele SSA-E triggers and I don't think they are really worth the extra cost.

Yes, you have to remove the grip with a long allen wrench. There's a spring and detent that needs to be removed so you can remove the safety selector to swap out the trigger. It's not hard.