The more I have the Michter's, the more I like it. It tastes "coppery" to me, like a horehound candy or molasses. I'm not really good at identifying flavors, so I can't tell you what "coppery" means other than it tastes like that to me. The Pikesville is similar, and only slightly more expensive. You can mix it down with water(I take it down to ~90 proof), so it might be the better value. These are both low rye ryes; MD style. They're sweeter, and more approachable imo. High ryes in the Monongahela style are drier, sharper, and more "grainy". Old Overholt is the only one recently I've had like that. An old Bottle of Wild Turkey from 80s was also a high rye, but I don't know if the newer product is the same, or if they even make it anymore. I've wanted to try some more high ryes, but haven't gotten around to it yet. Rittenhouse kind of splits them, and is moderately priced, but it just doesn't stand out for me. It's a solid whiskey at $20, but nothing exceptional.
tl;dr
Michter's or Pikesville depending on price. If they were objectively equal(same strength, generic bottle, whatever...) I think the nod would go to Michter's. Pikesville has the sharp looking bottle, and the higher proof will go farther by adding water.
edit:
Sagamore rye is pretty good also. They blend a high rye and low rye together to make a medium rye. I want to go on a distillery tour to ask why they do that instead of distilling a medium in the first place They just fired up the Baltimore stills this spring, so all the product on the shelves today is from MGP in Indiana, and it's mixed down with MD farm water. I'm looking forward to trying the 100% MD product. Their Moscatel bottling is exceptional, but it's limited release, and ~$90. Not sure that's a good one to start with for someone who isn't sure they even like whiskey. The standard bottling isn't as good as Michter's or Pikesville at approximately the same price. It wins points from me for being the hometown brand, but you wouldn't have that connection.