I know this post is gonna get me into trouble, but frankly - I don't care. I've been called a zealot, a bigot and lots of other names I didn't know about. I thank the people who threw those curses to my head, because without them I wouldn't have been able to expand my vocabulary with all these lofty insults.
Ok, why this lengthy introduction. Well, it's easy: FOSS programs didn't work for me. Ok, now I've said it. But it's the truth. You have to know that I'm a Configuration Manager and those guys do a lot of data crunching because their main job is to produce reports. And like it or not, but the main format they're processing and producing is MS-Excel. Users that want to have their data imported provide MS-Excel sheets and that's also the format they want to have in return.