These are two excellent knots. I use a Palomar often in saltwater applications using larger hooks. I've found fewer freshwater fly uses because I find it harder to finish on the small hooks (small eyes, actually). A gentleman on these boards recently offered some tippet rings for those new to them. I took him up on his kind offer and think I'll use the Palomar with them as tailingloop suggests.
The Orvis Knot is particularly underrated IMO. I use it regularly on most freshwater flies. I can tie it a little faster than a clinch, although it's really not much different than the clinch.