Assuming you're hunting SoDak, the lakes/sloughs are a lot like what we have in SW and Central MN.
My experience: a light 12' aluminum 'V' can weigh in around 125 lbs. Not sure how much a MoMarsh weighs or how steep the bank is.
Keys for me in this type of hunting:
1) V-hull- Even unloaded a jon boat is apt to catch waves over bow, stern, sides. Additionally, leaning over to grab a duck from the water doesn't lift the bow out of the water.
2) Row vs Paddle- better maneuverability with oars and better speed if you need to haul. I know, canoes and kayaks can be fast, but if the fear of God is in you I'll take pulling evenly against oars over one man and a paddle any day, particularly into the wind.
3) get a life jacket that has the mesh shoulders so you can wear it while hunting. If you sail one and want to go after it I'm always amazed how long it takes to get a life jacket on while reloading for a wounded bird, keeping an eye on it, getting the boat in the water, etc.
I pulled this up from West Marine:
http://www.westmarine.com/buy/west-marine--classic-dinghy--11985512?cm_mmc=PS-_-Google-_-Shopping_PLAs-_-11985512&adpos=1o2&creative=65739116644&device=c&matchtype=&network=g&gclid=CKfC5byEztACFQUtaQod8j0Bgg
When you're looking at late season, water over 3', and open prairie winds, I prefer to ride "high". Sneaks and pumpkinseeds, pirogues and kayaks, all have their place and I use various versions of all during a season. But having flipped a kayak (warm water fishing), submerged a Jon (ahh, youth...), sheared motor pins, had the wind come up while hunting the lee shore, etc., etc......
I'd prefer to hump an extra 50 lbs and have a bit more confidence in the tool.
If the slough/pond is such that the wind really isn't as big of an issue as just getting out past the point of waders, I use this:
http://www.dickssportinggoods.com/product/index.jsp?productId=12669143&camp=CSE:GooglePLA:12669143:12372990-DSG
ADDLE-SPORTS_KAYAKING_KAYAKS&gclid=CMez5YaJztACFYQ2gQod2poHJA
But it sucks for setting more than a puddler spread, which I drag a floating decoy bag along behind.