The Mini 4 is a good device. I just bought one 2 weeks ago to replace my fist iPad, the original Mini 1. That one still works acceptably though I suspected it was slow, and the battery was giving me fits for holding a charge in sleep, the push for me was it being dropped from the iOS 10.0 update path. As I travel and use a mix of WiFi services & tethering from the iPhone, it just seemed like a good time/excuse to do so. Just about everything is fast as should be expected from the first release.
The first Mini was a 64GB model and I barely used 34GB. I don't think is an option now with the Mini 4
If you have the time, around late November, Best Buy, Target & Walmart will start having Sales that will take some money off the list price from Apple's MSRP. I directed a friend to go that route last Christmas when her iPad was stolen from her Hotel Room Safe in Germany.
It paid for her to wait a few weeks to replace her iPad Air and saved somewhere between $125 & $175 by going this route.