Mark,
I've had similar experiences when buying less than top rate shells because I liked the design. LL Bean produces reasonably good stuff, but I bought a shell from them for its longer length and other reasons, and it totally wetted out after two days of a three month trek. Fortunately, it was from Beans, and they later gave me a refund, but the shell had to be replaced on the fly – a major inconvenience.
Come to think, there is a shell in the closet from EMS that looked super, but turned out to have virtually no DWR. Liked the design so much, that I kept it, hoping someday a really good aftermarket DWR treatment would become available. The shell is now obsolete, and just taking up space.
A WPB shell cannot transmit vapor if the outer shell is totally wetted out. So even assuming that the rain cannot get in, which is often said on these threads but seldom proven, your own perspiration will soak you if you perspire like most people (OK, there are some who claim to be able to comfortably wear coated WP shells). And if it is one of those very thin shells, you will feel drenched, even if water is not coming through, and will not receive the protection from hypothermia that is a main objective of a rain shell.
There are excellent reviews on this site of many shells that have come out in the last year or so. Including some that surprised me, like a reviewer's experience with the Montagne eVent Spectre, when I had assumed that anything made of eVent must be top notch. I have found these reviews, combined with good past experiences with some companies, like Patagonia, have led me to products with WPB that really worked and kept me dry. For those like me who cannot afford list prices for top rate shells, patient waiting for sales seems to be the most fruitful approach. Good luck to you in finding in good shell.
