I have severe arthritis and it especially effects my hands. I have a bunch of one handed opening knives and am always a sucker for another
I have the CRKT M-16 and it is good though the lock was sticky. I stopped by their office and they happily exchanged it for me and now I really like it.
I have a Buck Odyssey and it is quite easy to use one handed.
I have an old Al Mar Quick Silver which is very nice, but I am not sure they are still made.
Probably the smoothest knife I own is a Benchmade form the 1980s that was designed by Brend. Almost as easy as an assisted opener.
For assisted openers Kershaw gets my vote.
I have a I have a chive, which is a little small for my hand.
I have a Leek or two which are my favorites.
I also have a couple Blackouts, one serrated and one plain. They take a little getting used to as the assisting spring is pretty strong. At first it felt like they would jump out of my hand, but are great once you get used to them.
My overall favorite though is still the Kershaw Leek for size, ease of carry, comfort, and design.
There are a lot of knives on the market and most of them are at least OK. One thing to watch with the liner locks is that once you open them hard, some of them have a tendency for the lock to stick, making it hard to release the lock to close the knife.
I hope this helps.
Dale