And recently Apple switched to built in diagnostics... Its the base system, logic board board, and fan checks that is always important.... since most is on the board anyway, and even if you knew which part had failed specifically TTPro may tell you more, it wouldn't matter to most people unless u choose to "break your mac" by DIY'ing, Perhaps more would DIY out of warranty. but the cost of wasting your time, its easier to cough up the money to Apple/ third party repairer.No free demoes for TTPro, although feel free to contact Micromat. Perhaps they have limited-time demoes that are not advertised on their website.
Or, they may tell you why they don't offer their highest-level diagnostic software for free. There's probably some history there. Probably similar to why you don't get Microsoft Office (or Adobe PrintShop, etc) for free, either.
Even if someone sends you a copy of TTPro, you would need to provide a license number to use it -- and, if Micromat knows what they are doing, they would have software that checks for a valid license the first time you run the software.
Bottom line - if you think you need that diagnostic software, get it. Micromat (and TechTool Pro) has been around for a long time. They know Macs. New Macs came with TTPro in the box, years ago. You paid for that software, too, as part of your new Mac. The software works. Only $100.
I use it and have for years. Its a good piece of software. I recommend it.
TTP does not seem as necessary as it was back in system 8-9.x. OSX seems to run far smoother and with far less headaches as that Classic Mac OS did.