It's been a while since I collected comic books so bear with me. They release them monthly right?
I believe the schedule is a monthly release, yes.
I guess 2 is better than 8, but still im not sure I want to read the first half and then wait a few months for the second, it defeats the point of buying them as a collective.
Not really. It's still a collective with the 4 issues and the intent is then for you to buy the individual issues thereafter. It makes sense to me.
The good news about omnibuses is they don't go out of print as quickly as regular comics. Plus, while you can buy them in comic shops, they also get wider distribution (usually a few weeks later) via Amazon, Book Depository, etc. So you can choose to wait till both books are out if you like.
Remember IDW didn't have to put out two volumes if that's what they're doing. They could have made you wait till the summer of 2013 before seeing anything, if you weren't interested in buying the monthly comic. I say just buy the monthly comic and if you like it, get the collection. That's what I'm doing. That also goes for the numerous Doctor Who story arcs which IDW have already published in omnibus, all of which I believe are still in print.
It's a matter of patience. If you want to see patience in action, do some research regarding the "Cerebus Phone Books". These were omnibuses of Dave Sim's "Cerebus the Aardvark that usually collected anywhere from 15 to 24 monthly issues at a time, generally by story arc. As Cerebus is a single complete story that was originally published over 300 monthly issues, if you wanted to wait for the full collective, it was a 30-year wait.