I don't always like dropping cash for things that don't get used, but I did some of my own quick math...
I spent about $330 to get mine (about $250 + 1 week shipping from overseas).
Repair shop rates average $80 - $100 per hour.
Most shops charge 1 hour minimum.
Diagnostic fees, $150 (often waved, but only if they find something to repair and do the work - which is often more than 1 hour labor...)
Then add in things I mis-diagnose, buying parts I don't need and buying other parts I do need to finally fix the issue.
If I decide one part should fix an issue, buy it and the issue is not fixed. I'm in for the cost of the part + my time.
If I figure it has to be this other part, put that in and issue is not fixed... I'm in for cost of 2 parts + my time.
If I finally cave and bring it to the shop... I am in for 2 parts that didn't fix it, my time, at least $150 for diagnostic fees, any additional labor and any additional parts to actually fix it.
I may need help from the guys on the forum on some of the more in-depth functions of the Tech 2, but having it will allow me to dive in to individual sensor functions and diagnostic testing. If I can prevent myself from buying one extra part and avoid a total of 2 hours of shop labor... My Tech 2 will have paid for itself. $330 spent now has a very good chance of saving many times that amount over the next several years.
Nobody is forcing a Tech 2 on anyone, but from what I have seen and heard on the forum... Diagnosis and repair success rates are pretty convincing for people with Tech 2. If you are going to DIY the majority of work, it seems like the cost of a Tech 2 has great potential savings in time, money and aggravation.
I have not had to use my Tech 2 just yet, but I am ready and feel fairly confident it will be able to get me out of trouble some day. I'll be ready.