Most people who I have spoken with who build high hp Z engines use Total Seal. I have a set in my new engine and have had two previous sets in older engines. They are expensive, I paid $200 for mine. People who tend to talk bad about total seal have most likely installed them wrong. Before installation, you must wipe down the cylinder walls with lacquer thinner until completly clean and you must do the same with the pistons and rings. The Total Seal are to be put into the cylinder completely dry. DO NOT use any type of lubrication on rings/cylinders upon installation. If you do they will never seat, which is why people have complained. While talking to Don Potter, who uses nothing but Total Seal, he has performed leakdown tests on race motors with 2-3 seasons of use and had less than 2% leakdown. I would say it is worth it when you want to preserve the longevity/performance of the motor.
Just remember, that these rings use a different seating procedure than stock. And, probably the most important thing to do, besides keeping everything spotless when instaling them, is to size and gap the rings properly. If you fail to do these things, they will fail, just like stock rings. Done properly however, these rings can last a very long time.
I've run Total Seal in other engines, and was fairly happy. My new 3.0L engine is running Sealed Power with chrome top rings. Seem to work well for me, and come highly recommended.