looking at the various chip options at the moment, and was looking at some of the ECU piggy back setups which are available from brands such as haltech etc

my question is why dont more people choose piggyback ECU such as the one shown in the link below? from what i have read so far something like this offers more tuning abilities as well as being easier to adapt to other mods such as intakes, turbo upgrades, head work etc etc

or is there something im missing here? yes a ECU piggyback would require more labour cost to get it running right, but would probably work out the same/not that much more expensive than your big brands of 'chips'

what does everyone else think?

edit: added link
http://www.haltech.com/interceptor.htm