There is no comparison with regard to ride; a 600 micro rides like a Buick compared to any kart, since the micro has a full suspension. After the initial cost of the car, we spent about $6000 a year, from our engine program and tires down to the shop rag level. It is easy to spend as much as twice that, but we were lucky on wrecks, bent or broken parts, and only ever destroyed one engine. Our most expensive single night cost us $120 for frame repairs, $350 for a new wing, and $1250 for an engine out of a wrecked 636 Kawasaki to replace the one destroyed and about $80 in miscellaneous small parts. Since we already had the complete methanol converted fuel injection system, including a Power Commander, on the dead engine, it was just a matter of transferring it to the "new" engine. Again, we were lucky with our engine program and didn't get involved in a lot of really expensive wrecks, so we were able to keep costs down; bad luck can get you well over that $6000 figure quickly.
My drivers came out of the KT100 Yamaha class (and one out of the box stock Animal class) and that experience was sufficient to enable them to transition smoothly to a 120-130hp 600 micro with a 750lb minimum weight, but then none of them tried to win on there first night on the track - they all had a lot of common sense, which helps save money.
Learning how to use all those newly available adjustments is quite a learning curve; if you have access to someone who has been through it, use that friendship for all the knowledge it will save you from learning in the school of hard knocks.