Gizmos, or gadgets, or thing-ama-jigs, I'm a sucker like anybody else for the latest and greatest products, especially when they purport to save time and, in the case of this product, your back.
Being that I work by myself, I'm always on the lookout for ways to improve productivity, especially where time is concerned. That's the main reason I got involved in plasticulture, to save the time you have to invest in weed control, and it's why I purchased this Hatfield Transplanter from Johnny's Selected Seeds. I've purchased contraptions in the past that never lived up to the billing, but I have to say this product is well worth the money. Here's a photo of the transplanter:
A few things to keep in mind about using the transplanter: 1) It works in both bare soil or plastic mulch, but you'll need to sharpen the edges if you're planting in plastic mulch. I use a hone I can attach to a battery powered drill, and I resharpen after each use. 2) You'll need to play around with the depth stop because how deep your transplant is set depends on the force you use punching it in the ground, and also the tilth of your soil. My soil is a sandy loam so I set it a little shallower than if I had a clay soil. 3) Make sure your transplants are on the dry side (which should be the case if you're hardening them off) because if they're too damp the root plug can fall apart, which means you'll be hand planting them and moaning about all the money you just wasted! 
I made a short video of the transplanter in action here:
* Note about the video: Good actors are hard to find in the Tulsa area. I got this guy cheap because he was recently layed off by IEN, the Improper English Network. Go figure! 
Thanks for reading.
Pork & Greens