I come across this comparison quite alot. To me, it seems like an absolute no-brainer, bu there seems to be alot of misinformation out there. Here are some facts to combat that:
From Nengun; PFC £685. AVCR to control boost £367.
What you DON’T get for spending an extra £757:
Closed Loop Knock Control.
Twin Maps (full, not offsets).
Switchable MAFless load with AIT compensations.
OEM idle cruise and hot/cold starting compensations.
Up to date Windows software
Comprehensive online documentation.
On 97/8 ESL: AntiLag, Launch Control, Flat Shift and Traction Control for £100 extra.
ESL Cable Dongle and software: £95.
Datalogit cable and software £186.
The Apexi has 1 fuel map, 1 ignition map, has to retain the MAF and is much more expensive than ESL.
ESL is cheaper and has 3d boost control, full twin maps in which every parameter is duplicated, knock control, MAFless, diagnostics, closed loop fuel and idle and factory compensations.
Still seems like a no-brainer to me!