I just copied this reply that I had given last time this question was asked- The context is a little off because the dicussion had gotten a little out of line, but they are still my opinions.
I've owned both in many different configurations over the past 14 years, and if it is up to me, I will always own at least one of each.
The Ruger is a tool, a tool that I have used to put many meals on my table. I've had the same MKII (KMK10) since 1989. It has had well over 28k rounds shot through it and I have carried it in the field more than any of my other firearms combined. I bought this pistol because it was the only make I could find in this configuration at the time, and I had planned to upgrade to a Browning whenever they were being manufactured again. But, after using and becoming familiar with the Ruger, I became attached to it and it soon became the most useful firearm I've ever owned. To date, it has had many modifications/improvements and has required a few parts replaced that I had worn out, so yes, it has had a few jams and misfires over the years. But it has yet to fail at the moment of truth, and I know I can count on it, without a doubt.
The Browning compared to the Ruger is a Cadillac to a Chevette. If properly tuned, they are a true pleasure to shoot. I've owned two 5.5 Target models, a Bullseye, a Varmint, two Silhouettes, an Unlimited Silhouette (currently out of production) and I even bought one of the new Buckmark Carbines (rifle) in the target version. The accuracy potential of these pistols is unbelievable. The triggers are much easier to tune and other than that, no further modifications are needed.
Reliability between the two is identical. If kept clean and in proper working order, you should have no problems except for with faulty ammo.
As far as comparing the design and manufacturing, I've come to the conclusion that there really is no point in it. The Ruger has heavier parts and is probably a bit over-built in some aspects. The Buckmark has some plastic parts that are hard to stomach, but seem to be quite reliable. Takedown has to be learned with both, but it does with all other firearms too…so what, after the initial cussing and a little practice, it becomes old hat and requires no thought.
So, when it's time to go grouse or rabbit hunting, I grab my Ruger from behind the seat, and PRESTO! I'm huntin'!
And when it's time to boost my ego with some precision paper punching, my Unlimited Silhouette, (with the trigger set at just over a pound and the electronic sight dialed in tightly), comes out of its' case and is ready to compete, even with the rifles.