We purchased a coffee grinder mill about a month ago. We aren’t especially picky about coffee compared to connoisseurs. We wouldn’t buy instant coffee, but we aren’t the sort of people who need it to be roasted this week to enjoy it. Anyway, I accidentally ordered the wrong coffee on Amazon. I ordered our usual thing, but 6 bags of whole bean instead of pre-ground Gevalia traditional coffee. Amazon said I didn’t need to send it back, so we figured as long as the grinder cost less than it would have to buy 6 new bags of coffee, it would be worth trying.
I would say it tastes a little milder than the pre-ground stuff now than we’ve had it a few times, but I didn’t notice a huge difference. The coffee grinder itself seems to work well though, so I can generally recommend it.
Once we’d had it a few weeks, rather than it making the coffee we already drank dramatically different, it just made me more likely to want to try other whole bean coffees. I can very much recommend Small Lot Guatemalan Coffee from Trader Joe’s as absolutely delicious: 
Here’s the video: