Thanks for the responses. I think I'll get the 6. Esp since people are saying the 4 might struggle.
What people may not realize is that the Mini is not updated anywhere close to every year. The original Mini came out in 2012 and up through the 4 it did come out every year. However, the only difference between the 2 and the 3 was the addition of the Touch ID fingerprint reader, so the 3 had a year-old CPU on day 1. Similarly, the 4, which came out in 2015, used year-old hardware. So,
DO NOT BUY A MINI 4 as it is essentially 8 year old technology now and long past its useful life. It does not represent a good value whatsoever.
The Mini 5 came out in 2019. It's OK. It came out with a year-old chip too, but since it had been 4 years since the previous Mini, it was a much-needed upgrade... Especially for those of us who had older ones and were holding off on upgrading because they hadn't released a new one in four years!
The 6 came out in 2021. I have one, and I'm a big fan. They finally got the nearly-edge-to-edge screen like the iPhones, so the device itself is the same size but the screen is significantly larger than the previous ones. They also FINALLY went back to having the most up-to-date chip (at release time) in it, so even though it's only 2 years newer than the Mini 5, the tech is 3 years newer. Because of that, and the fact that it's not on the regular 1-year update cadence, I bought one immediately when they came out even though the 5 was still working OK. I don't want to be stuck with the same one for 7 years again like I was with the Mini 2 I had before the 5.
I'm always weary of buying electrics used or refurbed.
For what it's worth, buying refurbs directly from Apple is great. I've been doing it for a long time when I'm buying something that didn't just get released. It seems to take maybe 3 months after a product is released before they'll have refurbs available.
In any case, Apple's refurbs are the DOA units that get returned. They're fixed, given a new outer case and screen (only the "guts" are original), tested more comprehensively, and then sold. In effect, they're better than new.
I'll be mostly keeping it in the plane.
Is your hangar climate controlled? Keeping a lithium battery in a very hot or cold environment will take years of life off it. Better to keep the iPad in your backpack/briefcase, keep it charged up, use it for flight planning before you get to the airport, and keep it generally at room temperature for longevity.
GTN650 waas (are all 650s waas?)
All of Garmin's newer stuff is WAAS. The last thing that wasn't WAAS was the 430 (no W).
I have read here, and heard from others, I need cellular for the GPS and the largest memory. In the iPad 6 that puts me at $899 I think.
From your description above, if you have flight plan transfer and such, you have a FlightStream 510 in that GTN 650 in addition to the other gear you mentioned. That will also send GPS data to your iPad.
So, while you don't technically NEED cellular, it's a very nice thing to have for two reasons: 1) Backup GPS (no cellular subscription needed for this), and 2) picking up weather and/or downloading charts/data at out-of-the-way airports. I don't use it a lot, but I'm glad I have it.
That said, if you don't feel like you need a backup, and you can tether to your phone, then the WiFi-only iPad will probably work fine for you.
As far as space, you don't NEED the biggest one either. In fact, 64GB is plenty if you're only using it for ForeFlight. As with most technology, though, you'll use more and more space over time, and especially if you think there's any chance you might use it for something else, having that extra storage will keep you from needing to buy your next iPad for a much longer time.
So, take that knowledge and apply it to your situation. You may want the $799 top of the line iPad Mini 6, or you may decide that the $499 base model is fine.