I just went as a marshall at Ky Lake and Dave is correct. The three pros I went with all use Lowrance for sonar. One had HB side scans on his boat but used a in dash Lowrance for sonar.
I have a HB side scan and love it. I find it useful in scanning points for bait fish and for finding channels, etc. I bought the unit for the side scan abilities but had never had GPS before and find that the linking of the side scan with the sonar with the GPS is the coolest feature. Being able to weigh point on your GPS what you can see 100 feet to the side of you is an awesome feature.
I too have heard alot of complaints in the last few years about Lowrance's service department and quality of products, but I have also heard that they are working to fix that.
My only complaint with the HD side scans, and it is a fairly large complaint, is that in direct sunlight the screen can be difficult to see. When in lower light conditions the view is amazing.
Just my two cents for those reading this for purchasing information. I just went through that last year and everyone has an opinion about their favorites and I got a lot of conflicting opinions when asking. Made things confusing. If you are worried about quality of a product, you might find it helpful to call a repair place and get their opinions. I did this when purchasing a trolling motor and found it helpful. Don't know if that can be done with electronics as most are probably returned to the manufacturer.