I have owned Garmin, Lowrance and currently have a modern C80 RayMarine (with a Navionics Gold Chart Chip).
IMHO, the Lowrance with a Navionics Gold or Platinum beats them all, hands down.
Chart detail and ease of use, and mainly the color and presentation of the chart - absolute best.
BUT WHAT I WOULD DO IS LOOK AT THEM ALL WITH THE CHARTING SYSTEM YOU WOULD USE, AND COMPARE EACH UNIT! DON'T LET THEM SAY THEY CAN'T GET A CHART CHIP, OR ALLOW ANY OTHER EXCUSE. COMPARE EACH ONE YOURSELF...It's kinda a Ford/Chevy issue. Lots of personal opinion involved...