I have several Tamiya Evos and have had TC3 in the past. I have to agree to someone earlier in this post: TC3 is a really good car on a good driver's hand. I never did. I tried it for awhile and actually hated it.
I may sound biased but I preferred Tamiya instead of any other brand and as far as parts concerned, I would probably go with Pro 4 plus HPI has just came out with thicker chassis to fight chassis tweaking.
Here are some pros and cons of EVO 4 and Pro 4 that I have read in the past:
*Pros: easy to drive out of the box, BLUE, enclosed (parking lot, dusty, outdoor tracks) and open (carpet, indoor tracks) choice on gearbox enclosure, 3-piece main shaft system, multiple shock arrangement on the lower arms, TRF shocks
*Cons: Expensive, soft steel screws (strips easily), steel turnbuckles (pain in the ars to adjust especially with the thin wrench that comes with it), front arms breaks/not as durable as previous Evos, expensive (and limited edition) titanium screw set, TRF shocks is not blue
*Pros:Purple!, cheaper than any other shaft drive cars out there except for Yok SD, parts are widely available, competitive car out of the box (not sure about easy to drive out of the box though many Pro 4 and HPI enthusiast will probably say it is...I don't own one so I can't say anything), aluminum turnbluckles, stainless steel screw set (that won't strip as easily as Tamiya's)
*Cons:Chassis tweaking, Purple!, front arm breaking (I witness this myself), Stock Rubber is (fill in the blanks yourself), revisions, revisions, revisions....how many more new products they need to purchase in order to make it a better car?