I see that Lowrance is offering a $500 rebate on its BR-24 Broadband Radar and I'm thinking (with Defender's upcoming sale) this might be the time to upgrade my 10 year-old radar (and add fish finder I don't have). The HDS series displays come with Lowrance Insight USA cartography.

My question is whether Insight USA cartography is comparable to Garmin's Bluecharts which provide full harbor-level detail, or would I also need to buy the Navionics regional chart chips to get full harbor-level detail?

Any other comments from people familiar with these units?