The results of my expenditure:
A couple of days after Christmas, a box from Tripp-Pattison arrived with 3 new Cobra mags and 5 magazine conversion kits. After inspecting them (and finding everything to be pretty much as I expected, I installed the 5 conversion kits into 5 wilson magazines and loaded all of the magazines fully to get the springs to take an initial set. I then left the magazines loaded for about 1 week before unloading them and proceeding to the range.
The visual inspection of the magazine showed that the followers and baseplates were sturdy and well made and that the tubes appeared to be well made, although there were two minor nit picks I had about the tube:
1: the weld on the back was visible. I personally don't see this as a problem as the magazines inserted and ejected cleanly from all of my pistols. However,they did not drop free from a friend's 5" kimber CDP when loaded with one round. The ejected from the kimber when empty and spring assisted quite well. I did not figure out if this was an issue with the kimber, but the 8 roiund CMC power mags used by my friend dropped free with no issues.
2: there were 2 extra witness holes drilled through them below where the last round sits. I presume that this is a production expedient, but I initially was momentarily confused a couple of times when loading them up, as after putting in 8 rounds, a visual check of the mag showed some "empty" witness holes.
To offset these, the magazaine showed the initial virtues:
1: The positioning of the round relative to the feed ramp was better than expected and as good as advertised.
2: The follower allowed essentially no ability for the rounds in the magazine to nosedive (the tendency for the wilsons to do this on the last round was my primary complaint against them. (I believe that the long skirt, and the small bump on the follower which locks the last round in place fore and aft make for this)
I also found that the force required to fully feed a round in all of my pistols was subjectively lower with the cobra mags (I removed the recoil spring and fed several magazines full of primerless hardball rounds by hand to do this comparison).
At any rate, I then procedded to the range with 3 1911's and the new and newly improved magazines. at the range I fired a variety of types of ammunition, including UMC ball, 230 GR hydrashoks, 230 grain winchester SXT's, 230 gr +P winchester rangers, 230 GR +P federal tactical, 200 GR+P gold dots and some old reloads.
My commander went through 100 round of various types with no problems, although this weapon for some reason has always been reliable, so that doesn't provide a particularly good comparison.
Next I moved to a stainless colt 1991 which has been modified relatively heavily and has alway has problems with wilson and GI magazines, namely 12 o'clock misfeeds on the first round in a magazine and nosedives on the last round (I find that the wilson springs last about 1 month before this happens). At any rate, the cobra mags and the converted wilsons entirely eliminated these issues for this weapon, which ran through over 400 rounds in 2 days with no hint of a malfunction from any of the magazines. hopefully, the spring material and reduced compression of the longer tube will allow them to hold up over the long run.
I am very pleased with these magazines and would reccomend them wholeheartedly.