The Autel Maxisys 906 is great for the money BUT
.... Make sure you purchase it from a legit reseller such as AESwave. If you don't buy from an approved USA seller you will NOT be able to update it or get warranty support. Alot of amazon and ebay sellers are selling from different market's and putting the software on before it ships. You won't find out until something is wrong, you want to update it, you call for support, or try to get a warranty issue resolved.
Autel has a few variations of the 906 as well.
Scan Tools for Automotive Diagnostics available from AESwave, a factory authorized distributor for Autel, Launch, Bosch, AutoEnginuity, OTC, Hickok
As the shop grows you may find you need something else. Always make sure you can test drive before you buy. At one time I tried just about every scan tool on the market. Some of them could not do 1/2 of what they claimed they could. I made each sales person either let me try it out or I had them show me on a customer car. If the Bi directional controls don't work or were not available for what we worked on, the tool was nothing more than a code reader at best. Certainly not going to waste thousands on a glorified code reader....
I would stay away from Launch and Bosch for the Diagnostic portion. Code readers maybe, but not diagnostic.
All that being said. I ended up with Snap On. They do have various Scanner's options and they all have the same diagnostic coverage. The higher end units come with a scope built in. Like the OEM's, they are trying to get you on a subscription based system to access some of the features. Trouble shooter used to be a valuable feature that no one else had. They now make you access it through a website with a current Scan tool Software subscription. Some of the older vehicles still show some of the data but all the newer stuff is on the web. I haven't updated mine in a while but now they have something else they are trying to sell as part of it too. You can keep track of the repair order, see the code history from the scanner data and email it straight to the customer through one of there sites.