I'm thinking about getting a set of tire chains for my 2014 Sierra. 1500 with the 20" tires. Anybody got any that they really like?

Look in the owners manual. Some of the new pickups don't have enough clearance for chains, especially on the front. Others will allow the use of light car chains but not heavy truck chains. If you don't have the room for them, chains can do a lot of expensive damage under there.
A class S chain is for limited space. U is for unlimited space. Using a U where there's only room for an S is going to get very expensive.

Good info rockchuck. With that being said, I'll never be without a pickup that will allow the use of good ol heavy duty cam locks...That's what I run on my '04 GMC sierra in deep snow... 20" wheels on a 4x4 pickup. Give me a fu cking break..

What Rock Chuck said.

I had a 2009 Dodge Ram 1500, with 20" wheels, that I could not run chains on due to limited space between tires and wheel wells.

My current 2016 GMC 2500 has 18" wheels, and plenty of room between tires and anything else in and around the wheel wells.

I have an 08 Dodge 2500. The manual says to use S chains on the front. The stock tires are 265-70-17. I have 245-75-17. They have the same weight capacity and height but are a couple inches narrower which allows for the use of U chains on the front. I have lots of room with these tires.

Seems that there's also a class W chain. Here are the definitions. I have a set of very heavy chains that I picked up on Craigslist for cheap. The steel in the cross links is 1/4" thick. I think they were made for a skid steer or something. I have the room on both the front and back for them. You wouldn't want to use them for long, though. To say they're rough riding is an understatement. Luckily I've only needed them once.

SAE Class S - Regular (non-reinforced) passenger tire traction devices for vehicles with restricted wheel well clearance.
SAE Class U - Regular (non-reinforced) and lug-reinforced passenger tire traction devices for vehicles with regular (non-restricted) wheel well clearances.
SAE Class W - Passenger tire traction devices that use light truck components, as well as some light truck traction devices.

I have really thick chains that I got at John Deere for my truck. I got the largest links, and wish I got the smaller links. Anyway they are a bit of a pain to mount compared to the much lighter cable chains. I use those the most now, and really cant recall putting the big chains on the truck in years. I still carry them. Some type of chain is mandatory or you will get stuck in the state forest roads around here. When it gets especially deep or icy, I have been using cables on all 4 tires. I only have one set of thick chains. I also keep a set of cables in my Outback.
So I guess my experience is that cables are a big step up in traction from tires, and if you can't use chains, get cables.

Are you talking cable cross links or just cable side rails?

I've not been pleased with cable chains. My next sets will be v-bars.