Lowrance Mark 4 vs Humminbird PiranhaMax 176i FF/Chartplotter

I'm looking to buy and install an affordable fishfinder/chart plotter for my recently acquired Hobie Revo. I am looking for something that is going to give me a basic charterplotter, depth, and some idea of the bottom structure. I have been looking at the Lowrance Mark 4 and the PiranhaMac 176i by Humminbird. I've found quite a few reviews on the Mark and am aware of the issue with SD card not being water tight. However, I have not found much on the PiranhaMax 176i. Anyone have any experience withe Piranha from a kayak?

I use a 180 and its been flawless as long as my wiring is fine.  Definitely doesn't separate out fine details like is the school below me pollock or baitfish but it seems to mark everything fine.  I am definitely hard on my equipment and the Hummingbird pirhana max has worked great.  Eventually will upgrade but have been hesitant since I am hard on my equpment and my HB 180 has worked great so far.

The extra power (2200 vs 1600 watts) of the Mark-4 would be worth the slight price difference imho...especially if you're planning a "shoot through the hull" installation. I just put a thin bead of silicone on the SD card slot of my mark-4 and have not had any issues even after a couple complete submersions.

When outfitting my second boat I got a great deal on a Lowrance Elite-4 (color version)...never thought a color display was worth the extra money but I found it so much easier to interpret soundings...definitely a worthwhile upgrade .

I'd also tell you that I've owned both HB and Lowrance products and have delt with both companies customer service and found them both to be outstanding.