A simple answer to a loaded question? Not here!
1. For starters, I can't recommend the newest iPad AIr or iPad Mini. The previous versions worked perfectly though if you want to go the Apple route. That alone will save you a few bucks. Best Buy undercuts Apple prices by a few $$ and has bonus sales around this time of year.
2. You get what you pay for. I like the Samsung Galaxy Tabs a lot. Good hardware and software. App store has plenty to offer. You also have size options like you do with Apple. Since I have the Galaxy S3 phone, the Galaxy tabs are very familiar. The Surface (smaller one) is big for a tablet, it works great, but is subject to the frailties that plague PCs to some degree. I don't like the keyboard, but do like the kickstand. I don't know about the availability of Apps for the Surface, I think it may be a major downside to the device. The Surface is not cheaper than iPad either. As for the cheaper Tablets, they will be in the landfill before Apple introduces a new gadget (that's pretty often....) The Kindle is still primarily, an eReader.
3. Wifi or wifi and cellular - If you have a smart phone and can tether a tablet, you don't need cellular on the tablet. With more places offering free hot spots, wifi is more than adequate. ( I use very little cellular on my mini)
4. iTunes and the App store; I will start by saying I am cheap. If the App isn't free, it has to be really valuable to me or I won't buy it. I paid for Pages on my iPad 2 years ago and I bought a password wallet that syncs on all my devices on all platforms. Aside from that I buy music to add to the CDs I imported to iTunes. If you don't like iTunes and don't want to use it, keep looking at android tablets.
5. ios 7 - Never has Apple made such a big deal and been so poorly prepared to introduce a new ios. It has devoted Apple heads steamed. I count myself one and have had no problems with my devices, educated user I hope, or just really lucky.
6. I really USE my tablet. I use it for work, for financial management and communications. I rarely have to resort to the desktop as almost everything is possible on the iPad. I love it's portability! Documents and data flow back and forth with the cloud I never worry about losing anything or finding anything. Photos download automatically from my Android smart phone with Dropbox App and are instantly available to load on all devices.
7. If you are a big PC hacker type, the switch to ios is culture shock. The first time on the new iMac I was at my wits end trying to navigate. I only had to stop working so hard and it all fell into place.
My personal experience:
I have the iPad 2, (wifi only) and the first mini (with 4G LTE) and I had a 4th generation iPod touch and now have a 5th Gen iPod touch (which I really like a lot). My son has an iPhone 4S and the iPad with retina display. Both my sons have had iPods through the years.
My 50 year old eyes prefer the bigger screen of iPad 2 and typing is much easier. But I love the portability of the smaller tablet, so one for home, one for the road. Thanks to iCloud what ever is on one is also on the other, documents, data, contacts, etc. Retina display, my son has it, I don't, I can't say I miss it. It does make pictures look better, if you are a photo person, the retina display is worth it.
I also have transitioned from PC to Apple completely, I bought an iMac 4 years ago and it is as fast as it was on day one, no crashes, repairs, viruses. I just bought a Mac Mini and I also use Apple Airport extreme for router and I have an Apple TV (the only disappointment, I prefer the Roku 2)
I'm sure that was more than you asked for.....😉