Will be used for a 998SI and a 858HD. Which do you like better and why? My home water(s) is offered on both cards so coverage is not an issue at this time. Also is the Navionics Platinum that much better than the premium? I realize LM is a must if I choose to get iLink somewhere down the line.

I'd compare lakes and features and see which best suites you. Here is a link to Navionics WebApp that allows you at search lakes and see for yourself what data you'll be getting. http://www.navionics.com/en/webapp

 

Platinum is a great chip and you have the option to view the new Sonar Charts, which is user generated content. You can go back and forth between the two viewers on your Humminbird. You can also view Sonar Charts on the new WebApp and play with this new and very unique function. On the WebApp simply zoom in and check the little circle icon in the bottom left hand corner. Keep in mind, this is in it's early stages but here's a couple screenshots I got from another site that a gentleman got with only one trip to Allatoona

 

 

 

 

The goal for Navionics is that when a user records data and then loads it up on their website that they'll have it uploaded the next day. Things are off and running better than imagined and they are talking now like 2 weeks as they have over 800 logs they're catching up on.

 

The beauty of this add on feature is that those that want to participate can record data while out enjoying a day of fishing and those that wish to not, can still enjoy the benefits of those that did.

 

Also, mind you that when you purchase a new Platinum Card that you'll get a year of free updating. A simple process to gain the freshest data.

 

Hope this helps!