I don't know much about the rented pumps, but I will tell you my recommendation regarding a great breast pump and bottles. I got the Medela Pump'n'Style - double pump, so you can pump both breasts at the same time. For a working mom, every minute counts! The carrying case has a cooler where you can store the bottles on your way home (refrigerate them at work). It also has a car plug you can buy so you can sit and pump in your car if you prefer the privacy or the convenience. I loved that option!
Bottles come with it (but only four very small ones). I used the Avent System Bottles, and they offer many options and sizes for your growing baby. They also have lids you can buy that convert to the size of the opening of the Medela pump bottles so you can pump right into the Avent bottle itself.
I pumped for 10 months for my daughter, as she wouldn't nurse from me. Long story. Anyway, I didn't go anywhere without my pump - it went on many plane rides, and on every excursion from the house. I used it like crazy and never had ONE problem! It was probably about $250 and worth every penny!
There are also bags you can buy to steam clean/disinfect bottles, lids, nipples, and your pump parts to keep them clean. They are amazing - I also used them to disinfect my daughter's pacifiers. You could easily fit one in your pump bag or purse and they are good for about 20 uses each. Just add 2 ounces of water to the bag with the parts you want to disinfect and microwave. Ta-da!
There are so many products out there, I just wanted to share my story and my recommendation. Congrats on your upcoming arrival and enjoy every moment. They go by way too fast!