That Snap-on is the same as the Nexiq correct?
I think the only other options are Texa and Bosch. Both will be in the $7-8,000 range. There are some Chinese tools from Launch and Autel that claim to work with HD equipment, but they seem to only support Asian origin equipment.
The only way to really get OE coverage is with an OE tool. But, you might have 6 figures wrapped up in buying all the diagnostic software you want.
I think most shops will have the OE software for the stuff they use the most such as Cummins Insite or Cat ET and then get by with the aftermarket tool for everything else.
The nice thing with cars is that you can buy a J2534 pass through device and then use it with any OE diagnostic software which you can typically "rent" for one or two days at a time for anywhere between $50 and $200. Some companies like Honda even let you do ECM updates for free.
