If you are not happy with the lenses, you can sell them off, and still have a good deal on the 70D
I recently bought 55-250 STM for when I want to go light. I can say I am impressed with it, as yogestee is with his 18-135 STM... as a general kit lens.
If your not happy with the 18-135 STM, you can contact me as a possible buyer...
BTW.. The 18-55 STM, makes for very nice Macro work
Both shot with the 55-250
Best of luck with your decision
Happy Shooting !



