Ok. Reason not to buy a Tekin.
1.They're cheaper systems that produce the same results.
No, there are cheaper systems that come close.
2. If you do not have access to a lap top, updating can be a PITA.
There are MANY MANY drivers at my club who use an RS, who don't bring laptops, and do just fine. Why? because those of us with laptops love to help. I update / change settings on multiple people's ESCs every race weekend. This isn't a reason to not buy one.
3. Not a spec class esc, depending on where you race.
This has nothing to do with the performace of the ESC. if your club specs ONE model ESC, then every single model BUT that one wont work for you. This is a pointless bullet.
4. You will never get close to what you pay for if you decide to sell it. Big loss.
100% wrong. The Tekin RS holds GREAT resale value. Just go look at the for sale forums.
5. Red in colour.
Yeah, its red and black. This is a reason to not buy one?
6. Once your wife or girlfriend finds out how much you paid for it you will never hear the end of it.
7. Constant updating will last only so long before they release another esc, which will probably be in the Calandra range.
This is a disadvantage in comparrison to those companies that release a new model ever 6 months?
8. You will hate it after your first loss to another cheaper brand esc.
Yep.. whenever I lose a race, the first thing I do is blame my ESC, and then hate it. 
9. Poor led configuration.
The LEDs are fine
10. Crappy cap.
The cap was chosen specifically for the RS for its discharge characteristics and works perfectly. It's small and inconspicuous.