Reach is ten bucks American. If you buy the whole MCC, you get all the games for 40 bucks. Otherwise, buy them all separately for ten bucks each (plus 5 for ODST). Can confirm. You do not have to "buy" the MCC separately. Buy Reach, and you get MCC with only one game enabled. Buy the 40 dollar MCC package, and you will get all the games once they come out.
Let's talk about the game itself tho... Hooooly crap the player inertia feels super weird on keyboard and mouse. If you don't know what I mean, the player is "heavy." It takes a second for your character to start moving, which means the normal "ADADADA" strafing that you'd normally do in a PC shooter doesn't work. It also makes turning and shooting a little weird. You have to really feel it to know what I mean. It's clearly still meant to be played with a controller. Or rather, no changes were made to make it more friendly to a mouse and keyboard, which can be a good or bad thing depending on whether you're a purist or want optimizations.
Which brings me to the next point, auto aim is applied if you're using an xbox controller, and KBM players are put into the same lobby as xbox controller players. So there will be some interesting interaction there. A good player with sticks will probably be able to outdo a mediocre player on KBM. Of course a good player with KBM will probably always outdo a good player with sticks, but it will at least give the sticks a chance, maybe, especially with the weird inertia feel of movement that's clearly geared towards a controller.
Third point, steam controller: There is AWFUL input lag when using it with dual input mode (i.e, analog stick plus mouse emulation). Consensus seems to be that it's because the game does not support dual input (i.e., holding a controller in the left hand and a mouse in the right hand) and so the steam API is doing some gymnastics for it to work. I haven't tried it yet, but other say if you turn the steam controller to keyboard/mouse emulation (stick becomes "digital" and not analog) then it works fine.
Other than that, had a good time on the few games I got to play last night. Looking forward to more. Also, it runs great at 60fps locked even on my living room PC that's rocking a GTX 770 classified, and usually only used for low end games. So potato computers can definitely apply.