So occasionally, I find myself passing through this area, and did wonder every so often about this place. And since I wasn't the most aware about places to eat in this area, thought I'd give them a try one morning.
I have to say, I was quite surprised. It was very clean(and bathrooms also were as well, which isn't always the case at some Greek diners I've visited), very affordable, staff was very friendly, and you can EVEN order grits here if you want(which I did, and they actually have a decent version). My country fried steak was also good, though I almost went for one of the pancakes(next time?).
I'm 99% positive this place accepts cards(and could swear I saw a credit card sticker somewhere), but can't remember for whatever weird reason(so didn't vote on that under tips, but I'll confirm that next visit). And the hours are something like 5am-3:30pm every day, or 5:30am-3pm(another thing to confirm next visit).
Finally, though it doesn't appear that way when you get off at the Miller South Shore stop(as you can't see Jonathan's directly from that train station), it's actually walkable from that stop, and directly east of a McDonald's around one curve on US 20(Melton Rd, and after that slight curve you'll immediately see it). I know I'll definitely return here, at some future point.