My ST165 has been my daily driver for over 9 years, and soon I'll have put 100k miles on it since I've owned it. So yeah, it can be a fairly reliable daily driver. However, things do break and/or wear out. The only time it left me stranded is when I forgot to plug in the alternator cable after the regular replacement. It ran fine for a day and a half... then died a few miles from home when the battery died.
My first problem was an idle speed that hunted between ~700 and ~1500 rpm. I took it to a shop down the street (recommended by co-workers) and it took them all day to figure out that "if you pinch this hose just the right amount with vice-grips, the idle stabilizes." I took it to a shop that specializes in Toyotas (at almost double the hourly rate) and they identified the problem in about 30 minutes.
So, two lessons: 1) if you are not going to do all the work on the car yourself, at least find a shop with a clue. It can be a prohibitively expensive car to own otherwise. 2) Learn everything you can about the car and do as much of the work on it as you can yourself. Even qualified mechanics (if you can find one) are expensive.
Craftsman grade tools usually pay for themselves the first time you use them vs. paying a "mechanic" to do the job. Snap-On grade tools take just a few more uses to pay for themselves. So don't let the price of tools deter you from doing your own work.
I didn't know about the GT4 Yahoo group when I first bought my car, and I don't think this forum existed then, so I was slow to learn about the car at first. But with the great group of people on this forum, you can ask questions about anything where search results are lacking and usually get an informed reply. I learned a lot on the Y! group and I still learn a lot here.
You've come to the right place.