I've been very happy with mine. I buy the cartridges in boxes of 6, so I never really have to wait on one to do an oil change. I also keep a few of the O-ring seals handy.
As with a lot of things, opinions can vary greatly on the benefits and drawbacks of using these filters. I really really don't like the idea of unfiltered oil going through the engine. It's just my opinion, but when that by-pass opens, how many particles and junk is it carrying with it that were trapped in the filter? When there's a sudden rush of fluid, it tends to carry previously latent material with it. I see that as a big negative. I do know that a lot of guys don't have any issue running bypass filters, and I run them on all my regular FE's. The Mustang gets a lot of street miles, but also sees a fair amount of racing. When doing Drag Week, it'd get 1000 street miles and 7 or so runs down the 1/4 in a week, so I wanted the best filtering I could get, and I didn't want a bypass possibly sending junk into the engine before a 200-300 mile trek.
As for not flowing when it's cold, I crank my engine for 5-6 seconds and then I start to see the needle move. At that point, I know there's oil flowing into the engine. Then I fire the engine and the pressure comes up right away. I don't see any issue with cold flow, even with the 15w-40 that I run. I've also used a straight 30w with the same results. But I do NOT rev the engine at all until I see the temp come up to about 140 or so. I keep it at a low idle until then.
The filter itself is a fiber mesh that is wrapped and layered in about 4-5 wrappings, so there is plenty of surface area. I have yet to see the first layer get any amount of debris to affect flow or pressure, and if somebody were getting enough of anything in the media to allow pressure to drop, on ANY filter, then you have much bigger issues, or you're simply not changing it often enough. No filter should ever get to that point except for 2 reasons. 1: You're pushing a lot of crud through the engine, or 2: you're going years on end, or thousands and thousands of miles above what you should be, without changing it. Neither of those is acceptable.
I have a Moroso Accumulator that I'm going to install, which would pressurize the system before starting and eliminate me even having to crank on it for several seconds.