I'll let Trada's product speak for itself.
One basic difference is that from the advertiser's perspective, Trada is an agency in which you've essentially outsourced your marketing. However, AdGrok is a tool you can use to manage your own campaign. It can serve either as your stand-alone SEM tool, or as a complement to your existing SEM workflow.
Either way, you get an unparalleled view into what's going on inside your campaign and why.
We also have a managed service offering called GrokMe, in which we set up and manage your campaign for you. That's more in the agency vein, and from the user's perspective, similar to Trada's offering. Again though, even GrokMe users get our GrokBar and can see what's going on at all times.