I now use Amsoil myself but that's because it's a new engine (25K miles on it now), it's got a turbo and I'm babying the car as it's an '86 that I plan to keep at least 10 more years as my daily driver. Its original engine still ran but had the notorious piston knock that the older turbo 4 cyls get and it being my daily driver, I didn't want to take any chances on long trips, etc. The cars original owner didn't maintain the car well (did 5K or so oil changes), didn't even bother to check/add oil in between oil changes (saw the car 4 qts down once with oil light flashing, wasn't even in for that at the time), the radiator once blew apart on me one 100F degree day on the freeway (AC on) at high speed so when I saw the guage, it was buried in the red. Engine was also running a 15 PSI boost (double spec) for years. That engine STILL lasted to almost 200K miles before I decided that I'd prefer a new one instead and that engine used petroleum oil (no synthetics). I've had other cars that used petroleum oils with close to 200K miles as well (like yet another old 744 that I have) and even old GM cars too.
With proper maintenance, I'd say that most "well built" engines are capable of going 200K miles. I never warm up an engine prior to driving UNLESS it's winter, very cold outside and I want to get into a warm car rather than freeze for 10 minutes, especially if the wife's with me. I then don't warm the car up for the engines sake, but for comfort only.