Except....do not replace any Esky parts with "new" Esky parts always upgrade to a better part (often for less $ then the Esky part). Ok excluding bearings, frames, hard parts (bearings) etc like that.
Only talking from experince... only thing Esky makes that is worth upgrading to is the motors and for the price they can match anything out there ... Also from experience of having over 10 popular motors that people have touted in these threads in my heli and 3 ESC (low end $ point with desirable features) to run them with. $ for $ its hard to beat the Esky 3800 3900 motors if geared correctly with the right ESC.
Soo much time on my hands, so I Easter egg parts for fun and entertainment ..