Do you have other instruments that the sounder might need to talk to?? If so, getting the same brand as your other instruments might be wise.
Do you have a chartplotter? Some of the small Garmin chartplotters also have depthsounders...and if you were looking to get a chartplotter, getting a combination unit might be a good solution.
Last year, I replaced my Raymarine ST60 gear with TackTick gear, mainly due to serious problems with the wind instrument. The TackTick gear, while a bit more expensive than some other brands, was also much easier to install, since the wind transducer didn't require running wires up the mast. Either did the display heads, since they're wireless. Might be worth looking at...since expanding the system is far easier than any other brand.