seeing as a MHRV system is basically a mechanical extract system with and additional advantage of heat recovery, i cannot see how it would make economic sense to install any mechanical extract ventilation without having heat recovery as a feature.
if you dont want heat recovery, just put in hole-in-the-wall vents.
My reading of the iMEV is that it is simply an 'intelligent' extraction system and NOT an air supply system. If you use this you still need some kind of air intake.
The aereco systems seems slightly better, but id be worried about the lack of Uk or irish certification, because we have significantly higher humidity levels than the countries it has certification for. A certifying engineer / architect may have issues accepting a system that is not certified for use in ireland which deal with such an important issue.