I don't know that my answer is going to be all that helpful, but it's my experience so take it for what you will!
When I had my son I attempted to nurse in the hospital, it ended up that he had really bad reflux, but basically what happened was I was nursing (and doing pretty well) and suddenly he stopped breathing and turned blue. Now, I'm an RN, and when I say blue, I mean blue, as in blue and dusky, and generally not good. He ended up in NICU ruling everything other thing out (and did it a bunch more times with bottle feeding) but I basically was freaked out about the whole stopping breathing when I was nursing and I just couldn't do it. In hindsight I know the nursing had absolutely nothing to do with the problem, but hey, I was post-partum and post section and not thinking all that clearly! So, I decided to pump as much as I could and supplement with formula.
I have to say, it was a disaster. I never was able to pump very much, I was pumping every 2-3 hours and having to wash everything from pumping then feed my son, then wash his bottles. I felt like all I did was work on feeding him! After about 6 weeks he was doing well on medications and no longer turning blue nearly as often so I decided to try putting him back to the breast. Thank God, he actually took to it, I didn't think he would, but I still only nursed with him on his apnea monitor so I would notice faster if he stopped breathing or his heartrate dropped too low from lack of oxygen. Anyway, it was my first child and I just was never confident that he was actually getting enough and ended up supplementing still and to try to keep production up I was pumping after each feed, so I was still spending most of my day focused on feeding.
After I went back to work part time things actually got a little easier. I pumped as much as I could on days I was at the office, nursed at home, and just resigned myself to doing a mix of formula and breast milk, then finally at 6 months I threw in the towel and switched to all formula (and solids.)
So, I would say that attempting to exclusively pump was a disaster for me, but on the flip side I do know other mama's that have made it work! My thought on the issue is that I love the benefits of breastfeeding, it's a great thing, but, when all is said and done I was formula fed, along with millions of other children around the globe and frankly have turned out okay. Yeah, I like the cost savings and I hope to have success with the baby on the way, but if it's stressing me out and I'm not getting any sleep or time to simply bond with the baby because all I'm doing is washing pump parts and bottles then I'm just going to formula, bonding time is important! Good luck with your attempt, I hope it goes better than mine did, you probably will have better luck if you have nursed in the past and know your milk supply is at least in.