I find the GPS invaluable but I fish from my ski so it is great for marking spots I want to fish. Coupled with the sonar I can look at bottom structure and identify fish and bait schools. If you are just cruising local water ways probably a bit of over kill. All GPS come with basic mapping but to get the best out of it you need to purchase quality mapping software such as Navonics which will give you all the contours, navigation markers, go slow zones etc. etc. just like a paper chart. They are great for locking in where you want to go especially across open water as you get a heading to follow by way of a marked line on the screen so you can steer a straight course. They also mark your track so if in tricky water or low visibility you can just follow your trail back home. I have a Lowrance Elite 5 CHIRP which gives a 5 inch colour screen. Me personally I would stick with Lowrance or Furuno and anything bigger than 5 inch is hard to install on a ski.
If you just want a mapping system and you have a water proof case for your smart phone Navonics have an app with all the same maps you can get for a GPS costs $27. Great for planning trips while sitting on the lounge or train.
I downloaded the navonics app on my phone, it looks great and a lot cheaper than installing a GPS combo on my ski
I have yet to test it out on the water thought [emoji15]
Does anyone have any recommendations for a decent phone holder? (IPhone 6) I would prefer a stick on type (for easy removal)
I could either leave it in my waterproof pouch or have one that is waterproof
The only half decent one I have seen so far is the ram mount systems
Im also a fan of Navionics- not a bad buy for $25 in my opinion.
I have a Ultra 310r so mounting options are a bit easier for me. I recently purchased this the other day http://www.over-board.com.au/waterproof-phone-case-and-bike-mount.html and have used it for two hours on the water the weekend just gone. It's fantastic! Combine this with navionics and you've got a poor mans chartplotter right there. I have also tethered the case with the included rope as extra safety in the event it does unclip it self although I doubt that will actually happen. It also means I can carry my phone to the beach and have less of a panic attack should I (or namely my kids) drop it!
I must say that I do only really use it to just confirm what Im seeing in front of me...
I also really recommend the beacon to beacon guides- they're fantastic.