I'm asssuming you're talking about RJ45 crimping tools. If so, the only one to get is the Platinum tools EZ-RJ45. The plugs allow you to push the wires all the way through, so you know that they are in the correct place, and not caught halfway in. The current featured tool section shows how the wires go through. The only thing to watch out for is that you get the correct connectors for the wire you are using. Cat6 and greater uses a different gauge wire than Cat5E, so you need a different connector. Trust me, I learned this the hard way.
I've been using a Ideal Industries Telemaster 30-496 for years with good results, and it will also allow use of the wire-thru connectors. It also has an RJ-11/13 crimper (up to 6 wires) on it and a wire stripper/cutter blade. And a lock to keep it closed. I think I even saw one for sale at Lowes or Home Depot recently.
I like the EZ-RJ45 stuff (the ability to stick the wires through the connector should make the whole process faster and easier) but I've never used one. I don't need to make enough cables to justify the cost.
I've been using an old plastic Radio Shack crimper for RJ11/RJ12 for many years (I think it's 19 or so years old now).
For RJ45, I've been using the one that came with 1000 feet of cat5e from www.geeks.com. It's worked well enough and it was cheap.
I prefer to buy patch cables and use jacks and a punch-down tool for the ends of runs that I need to make.
You should be able to get theEZ45 at all the usual suspects. AutomatedOutlet and Worthington are probably the cheapest. OnQ also sells it, so any OnQ dealer should have them.
Or as Huggy points out, you can just use a regular crimper with the EZ45 plugs. You just need to cut the ends off manually (the end result won't be quite as pretty though. becuase the cut wires will protrude slightly).