Which Fish Finder

A friend of mine gave me an old Lowrance LMS 339c iGPS Fish Finder with sonar and mapping GPS, water temp, boat speed and able to record trip, also came with US lakes SD card. I already have installed with Ram mount and transducer mounted in scupper hole. I was in Gander today and they have a Lowrance Hook 4X fish finder for $140.00, looks like it basically doe the same as mine but smaller and with chirp Technology??? what ever that is, also it has down-scan??? again don't know difference. Is it worth it to buy the new Lowrance or should I just stick to the old one, which seems ti be working just fine??

Thank you in advance for the help!

I never really learned to read 2D, regular sonar growing up. Im getting better at it now after being able to watch a split screen with down scan. Down scan when adjusted properly will give you a true "picture" of whats under you. You will be able to actually see the trees and other structure under you. I rarely use 2D with my set up it's either set on down scan or side scan. Another tip if your looking at spending the money and you think you will use a graph for more than seeing depth and other basic stuff get the largest screen you can afford, save a little longer and go bigger. The screen size really matters when it comes to being able to see details. I had an Elite 4 with down scan and GPS. It was a nice unit but trying to watch a split with sonar and charts at the same time trying to relocate something I had marked previously was tough. If you are not in a hurry to get one wait until the Black Friday sale at Tackle Warehouse. It's a very good sale with most everything on the site being 20-25% off including graphs. I got my Lowrance HDS 7 Touch for around $600 cheaper that way several years ago and Im going to upgrade that way again this year. A good graph is a very useful tool. I was catching some good fish on some off shore rock piles and ledges that without a good graph I probably would not have been able to catch. I was able to see which piles and where on the ledges they were then turn around and target them.

Thank you Mr Ray, great information. I'll take that into consideration!