Congrats on your Bushy. Fine choice by the way. I purchased the Varminter 2 years, right before the predator came out. If I would have known about its coming, I probably would have gotten that. Anyway...
I have done a little load development, not nearly as much as I have wanted though. As far as factory ammo goes, my gun loves the Winchester White Box ammo in a 45 grain hollow point. I can shoot right around a 1/2" when the conditions are right. It is not bad price either, $15 to $20 depending on where you are located.
As for handloads, mine really likes 52 Grain Sierra Matchking Hollow Points on top of 27.5 grains of Win 748. It is not a max load, but it is an accurate load. That one will shoot about the same as the 45gr Winchesters.
Don't be afraid to try light bullets too. I was very surprised to find that that is what my gun prefers. I figured that with a 1-9 twist, I would have to shoot a little heavier bullets. Not the case.
As for reliabilty, anything will cycle through the gun with no problems. I have never had a jam.
Have fun with it. Be very careful though, they grow on you and you will want another one!