If they are so good then why did pachmayr who also made them quit making them?
Pachmayr never made grip adapters like the Tyler T-grip; they made a hard rubber adapter that didn't last as long and didn't fit as well. T-grips are (or were) an inexpensive solution to the ridiculous shortcomings of factory grips. Though they are no longer particularly inexpensive, they still alleviate, to a degree varying with the individual user, the failings of service and Magna grips, and similar failings of some Colt and Ruger products. For those of us who want to keep the original factory grips, but want to actually be able to use the revolver, they are often a good solution. Sometimes they are even the best solution, offering the smallest usable grip. This is often the case with J-frame Smiths and D-frame Colts.
As for fit, I have had a few Tylers that, in each case, did not fit satisfactorily on one revolver for which it was designed, yet fit satisfactorily on another example of the same frame. Do you think that this was because the Tyler changed shape, or had a personal disagreement with the first revolver, or could it have possibly been because not all Smiths ended up with exactly the same shape of frame? I happen to believe the latter. It would then follow that it is not Tyler's fault that S&W couldn't make all their revolvers the same shape.
You certainly should not buy Tylers if you don't like them, particularly at their present price, but they serve a purpose for some people.
"De gustibus no disputandum est," which I believe is Latin for "Don't spit on your goose."