No doubt Eon is a nice car and I differ with you guys about Alto 800, it is also an excellent car except looks which are subjective again, but the kind of long term reliability,spares,service cost which Maruti provides no other can at the moment, so it is VFM and peace of mind car.
To compare Eon with Alto 800 properly, then it is better to compare both with 1 year ownership costs and reports, then I am sure 800 will be a winner.