frustrated with dealer maintenance

Can't help you there. My HD (VRSCD) has a hydraulic clutch. My Vulcan has a cable (which I prefer) but I'm not having any issues with it.

My advice spans almost all motorcycles and cars. Either pay for your service as tumbleweed advised, or....Buy the Factory Service Manual - or in cases where this is prohibitively expensive (Like maybe the G3) buy a comparable aftermarket publication. Then familiarize yourself with the maintenance schedule.
Armed with this, and maybe $100 worth of tools that you probably already have, you really can save yourself a ton of money, and NOBODY will (or should) perform inspections on your car more thoroughly than you.
The Prius, like almost every car manufactured after the turn of the century, has a very light maintenance schedule. For the first 100,000 miles, it's almost all fluids and filters. Where a FSM will save you a ton of money are the inspections and minor adjustments that are called for by the maintenance schedule, but almost never performed by all but the most dedicated gen-u-innne factory certified technicians. We call this "gun decking" in the service, and it's especially critical with motorcycle maintenance. Unfortunately, almost all factory technicians get paid a flat rate for a specified X-mile (or km) service. This means if they wham through the 'change the oil' part, and maybe aren't so diligent about checking the other little things, they can do more work in their 8 hour day.
Stuff gets skipped.
If you have an older vehicle (G1/G2 Prius), then a FSM and your tools will very quickly pay for themselves when you enter the "repair" instead of "maintenance" stages of car ownership. At the very least you may be able to more accurately diagnose a minor problem and repair or replace the broken piece/part without having somebody just start buying parts and diagnosing by replacement (we call this "Easter-egging' in the service! )
In the M/C world, it's much worse. A proper 3K service, Harley or Import, usually involves one oil/filter change (maybe air too) followed by about an hour of visual inspections and adjustments that can be performed by almost anyone who knows how to read, and has a few tools......if they have the manual. Belt tension, cable adjustments, fall-away measurements, etc. this is why the typical 3K service for a motorcycle is usually more than $200---in case you G3 drivers feel victimized by your $75 oil changes...
YMMV, BUT in the end YOU are going to be more motivated (or should be) to take care of YOUR vehicle than some factory trained wrench swinger or (worse!) some Iffy-Lube employee.

Good Luck!

 

This is mostly the same case for me as I haven't checked the torque on the oil drain plug nor filter. I have checked the oil level after change and only had one dealer (who I've never gone to before, but did it out of convenience when I was in LA, at the convention center for a convention) overfill. Sometimes one of the dealers I've gone to has done stuff like rotate my tires or changed my tire pressure when I directed them not to.

Agreed. I usually dig around for reviews and stay away from the ones that seem to have a bad rep.

Of the dealers I've gone to for maintenance, repairs or warranty work, I've generally been satisfied.

 

Two very useful tools are a decent quality trouble code reader and Google. These days I would use Google before I go to the shop manual to trouble shoot based on trouble codes. I prefer a code reader that works with a laptop or netbook instead of a handheld.

Odds are your problem is the same problem many others have had and posted in forums that Google catches. The shop manual will take you to a particular system or circuit but there may be more than one possible source for the trouble code in the particular system, odds are you will have the most common one