I LIKE THEM A LOT.
I started canning about 8 years ago (or maybe longer? I cannot remember) and have always used the metal lids. I was so excited when I learned that I could [after carefully inspecting the used lid] get a few uses out of those lids before they needed to be thrown away. It seems the way they make them now though, I can only get one or two uses before they are done. Of course using them more than once is NOT recommended. But ... we do it anyway.
These Tattler lids have been out for about 36 years. The only question I have is: Why did I only learn about them 2 years ago???? It seems I should have heard about them long before then!! Some might be shocked by the price. I paid about $50 total for 6 dozen lids and rubbers (half wide, half regular). That's about $.70 each; however each time you use them, the price per lid goes down and down ... and IF you can a lot, they start paying for themselves very quickly. Obviously if you do not can a lot, you might as well use the metal lids.
How long do they last? The plastic lids will last a LONG time [the rest of my life? longer?] and I believe they are guaranteed for life. The rubbers are in danger of drying out and cracking ... but I've read reviews of them lasting over 20 years before finally giving out, and the rubbers are cheap to replace.
Bonus: They are BPA free.
The only negative I can see right now is that if you are canning something you might give away, you will want to use metal lids. Don't count on people returning your tattlers!
I guess another negative for many would be the initial investment. I have well over a thousand canning jars ... and only 6 dozen tattlers!!! I obtained those by selling a nice wool coat on ebay. I kept the money in paypal and then used it to by the lids. I turned something I was not using into something I needed. Praise the Lord! Maybe you have something sitting around too that you are not using?? Do some deep cleaning ... have a yard sale or post on craigslist or ebay.
I have a few more items ready for ebay ... and will use the profits for more tattlers.
Here is their website: Tattler Reusable Canning Lids.
UPDATE: I decided to invest in more Tattler lids a few months ago with my income tax return money. Before doing that I did a google search for reviews on the lids. I was surprised to find mixed reviews - some like me who really like the lids and do not seem to have a problem with them and some who have had nothing but problems and would not recommend them to anyone. This of course caused me to wonder why the big difference? The only thing I could think of is user error. It is quite possible that the negative reviews were simply the result of not knowing how to can properly. That's an assumption of course but I think it's a safe one.
One big complaint I see is that the lids will unseal after a while of being stored. Now, don't get me wrong, I HAVE had a few lids come unsealed while in storage ... but I have had metal lids come unsealed as well. It seems the lids that get dirty during canning are the ones that are more apt to come undone, and this makes total sense. In order to prevent this, be sure to leave enough head space between the food and the lid. I leave an inch and that seems to do the job right.
Many have complained of failed seals right out of the canner. One cause of this could be leaving them to cool in the canner too long. Be sure to take them out of the canner as soon as they are ready [allow canner to cool naturally; gauge is at zero pounds and no pressure comes out when the weight is slightly tilted] and tighten the rings as per the instructions ... otherwise the whole batch, or most of it, is likely to fail.
Another possibility would be not letting the canner vent for 10 minutes before letting it build up pressure. Be sure to leave the petcock or pressure gauge open or off the canner till it has come to a boil and vented (not just a little bit of steam but constant, strong flow of steam) for 10 minutes, after which time you must close the vent, bring to the proper pressure, and maintain it for the duration of the canning. This removes all the air from the canner and allows it to come to the proper temperature.
Other tips -
Be sure the rubbers and jar tops are clean and free of any food stuff.
Be sure you are keeping the gauge at the proper pressure the whole time during processing. Irregular pressure can result in failed seals &/or spoiled food.
Remove air bubbles before canning.
Check for chips or cracks; discard if present.