Umm... It kinda depens on your level of experience with rc. I had a 06 pro and it was not a easy chassis to do maintenance with, especially when come accessing the rear diff. Due to my inexperience, my 06 pro had a leaky diff and to access it, you have to remove the motor, unscrew the rear stifener, aroud 6-10 screws on the bottom and 3-4 more screws on the gear box. By the time you done all that the entire rear end of 06 will be torn apart.
Besides the diff problem, wiring electronics will be Challenging(for my skill level). Literally cable had to.be wired between the main belt to solder onto motor. The motor choice will be limited too because solderong pads mptor will clash with.the left rear stiffener. Unless you use spacers and longer screws to imstall motor, speed passion and Tamiya' s motors will be the best choice.
Handing wise, the 06 is balanced and has very stable rear end. But to achieve all this, you will Scracifice a lot. While the ta05 with its straight forward and even more relevant design (yes, mid pulley is a trend now, Tamiya did that 15 years ago), wider user base outside japan, it is the clear better choice as long as you dont plan to go crazy with hop ups.