Although there are many other connecting links for installing and removing chains, I believe the Sram Powerlock system is the easiest and most universal. They have special connecting links for most chain types and speeds, to include Shimano, Campagnolo and Sram. Removing andor breaking the Powerlock is fairly simple with the use of a pair of plyers or a special tool from Park. It's always safer to use a new Powerlock link once it is removed from the chain.
The Powerlock link is outstanding. I bought several of these to make traveling with my bike easier. Now, I simply take the chain off when I disassemble my bike, clean it, and place it in a plastic baggie before packing my bike in my bike bag. The Powerlock links make reassembling the bike, and chain, extremely easy. I keep a Powerlock link in my Continental seat bag as well as in a Stickypod bike bag that I place in a jersey pocket. The Powerlock link makes fixing a broken chain simple (not that broken chains occur very often, but having a link that can fix the problem in a few seconds is well worth the few dollars that it costs).
Been using SRAM Powerlock Links for several years, but with 10 speed chains. Finally switched to 11-speed and bought two with my build kit. The first one I put on was very very tight and caused a problem with the chain passing through the rear derailleur. Replaced it with the second one and worked like a charm
I've never had the problem with them being tight on 10 speed chains and I suspect that I just unfortunately got a bad one.
My wife and I do a lot of travel to tour with a Ritchie Breakaway and a S&S coupled Ti bike.... that requires pulling the chain every time we pack the bikes. I use a Park tool (not sure what number) to open the Power lock (you can do it by hand but if new it is difficult) and re-use the links. We do maybe 500-1,000 miles every trip, so we probably re-use the links about five or six times before I replace the chain. Never had an issue with re-use. I save the old links and put one or two in my minimal road repair kit.. years ago a dropped chain got sucked and kinked, it was an easy fix to remove the kinked link and replace it with a spare Power Lock. The chain was shorter but it got us home. Can't imagine what I would do without these things.