Is the cab on the frame? Does that $2k include parts? If so, it's a great price otherwise it sounds reasonable and any shop that uses TIG welding is probably going to be more meticulous.
Both MIG and TIG will weld two pieces of metal together, but TIG is neater with a smaller bead and more control over burn through and penetration. The downside of the TIG is the cost of the equipment and complexity of operation.
