Spectra with conversion or Simply the Medela

I'm at the point where I need to choose my pump. I'm torn! I'd really like the Spectra S1 due to its portability and closed system BUT I've been reading on different websites and blogs that the customer service is less than desirable and replacement parts plus other accessories may be costly or difficult to locate. Since I'll be pumping a lot, replacing parts will be an absolute must for me to maintain my production. I've also read that the bottles have tops that loosen easily so I'm looking to buy the conversation pieces to use medela accessories if I get the Spectra. However, I can't help but wonder, why not just get the Medela? I've read great things about the customer service and the accessories are more than easy to find. Both pumps have excellent reviews online, this is why I'm so stumped. ***My pumping Needs--- I need a pump that has a battery and car adapter seeing as I will be pumping in my car almost exclusively due to my job. I travel to schools and homes, I do not use our office other than maybe once a week. I've already determined how to keep my milk stored and cold plus maintain cleanliness, I just need to know what my best option for the actual pump is.