Vexilar flashers are pretty basic but built like a tank and are all you really need to help you catch a lot of fish. All of the dedicated flashers are generally the same, except some have a zoom feature that helps you hone in on a certain part of the water column(i.e. bottom hugging bluegills).
I have a Humminbird Helix 5 and love it for the GPS/mapping. I also love it because I can use it year 'round, whether on ice, boat or kayak.
The best choice may depend on how/where you fish and what you fish for. You may be best served trying something used, seeing if you like it, and go from there. I bought a used Vexilar FL8 years ago, and it served me well until I found a good deal on a used Helix 5 with the ice ducer. I still have the Vexilar in case I have a friend or my son with me on the ice. For ice purposes I am glad that I upgraded from the FL8, because they do not do so well in shallow water(like less than 5') or in heavy weeds.