By corporate discount I mean that I get 13% off because my employer has a deal with Sprint/Nextel. The company buys such and such an amount of stuff from them, and in return for all the business, us peons get a discount on our service. If you are unsure about it, just call up Sprint and ask them if your employer has any discounts. They can do a quick search for the name of the company and will be able to tell you right away if there is one available.
FIMF stands for First Incoming Minute Free. I'm probably wrong, but I thought that this feature was commonly offered if you have an issue with dropped calls or wrong numbers, etc. But there's always a way to get it in any situation and it can save you a small fortune if you get a lot of short calls.
As far as phones go, I've only had my A920 for about 24 hours now, but so far I absolutely LOVE it (and I haven't even so much as touched any of the PowerVision features yet since my new plan doesn't go active until the beginning of the next billing cycle.) I personally was looking at the Samsung A900 originally, but the battery life is one of its biggest drawbacks. Even the salespeople at the three Sprint Stores that I went to warned against the A900 mainly because of battery life. The A900 also doesn't have a slot for memory cards, so you are stuck with the memory built into the phone, although I have no idea how much that is.
The A920 on the other hand has a TransFlash/MicroSD/really friggin tiny memory slot that they say can go up to 512 megs (confirmed this today after a quick run to Circuit City) and I have read on some forums that it can easily handle 1GB+ cards as well. This card makes life MUCh better since you are no longer forced to buy your music from Sprint. Instead, just pop the card into your PCs card reader and transfer your music right on over. The phone has no issues playing back the 30 or so MP3s I've tried so far, and it is supposed to also take AAC and something else that I can't even remember. The A900 I think can play the same formats, but the only way to get music to your phone is to download it from the phone itself and then you are limited to onboard storage.
The camera between both Samsungs should be the same deal, 1.3 megapixels, and not too shabby at all. Far better than previous generation camera phones, and with the A920, they can be saved right to the microSD card and then shuffled to your PC just like a normal digicam, bypassing the PCS Vision/PictureMail stuff from Sprint.
On the battery life side of things, I already mentioned that I have heard (read: NOT first hand experience) that the A900 has poor battery life. The A920, I am pleased to find, has quite excellent battery life during my first 24 hours of ownership. Today at work I was using it to play MP3s for at least 5-6 hours of the day and took quite a few pictures as well. In the end, the battery meter went from full charged (3 'bars') to 2/3rds full (2 bars.) Not bad if you ask me, and considering that this phone is acting as phone, camera, mp3 player, and when my plan changes over web/email/streaming media client.
Alas, I haven't even seen the Sanyo 8300, altho my previous phone was a Sanyo 8100 which lasted me a solid two years and is still in nearly mint condition.