Between a vexilar or Marcum it tends to be personal preference. Everyone has their favorite and they swear theirs is the best but the are both quality products so you can't really go wrong with either.
If you are comparing a flasher to an underwater camera your money is better spent on a flasher. Cameras are nice to kill time when the fishing is slow but from my experience they don't but that many more fish on the ice.
If you have no ice fishing gear yet the first thing I'd do is buy a gas auger. even with a flasher or camera you'll need to drill a lot of holes to find fish and a gas auger is a must if you are really going to go look for fish.
Here is the order in which I'd make large ice fishing purchases.
1. Gas auger 2. Flasher 3. Portable shelter 4. Camera
We use two Vexilars. We will find a spot and punch 10 to 20 holes (that's why you need a good auger) and hop from hole to hole until we mark fish and we will drop a line. While keeping an eye on that hole, we will keep checking the other holes with the other Vexilar until we graph more fish and will drop a line down that hole. This can be very effective as you leapfrog from hole to hole. I've seen a limit caught in less than an hour this way.
got most everything i need Clam Youkon, Jiffy 10" auger and some rods but here in IOWA we just drill 2 holes on top of a tree and catch gills or crappies fish mostly small farm ponds, will be moving up north in a couple of years and getting everything together before we move. Thanks for your info good luck on the ice.
Three-fourths of the Earth's surface is water, and one-fourth is land. It is quite clear that the good Lord intended us to spend triple the amount of time fishing as taking care of the lawn. ~ Chuck Clark