Although we have yet to directly experience our choice, we spent quite a bit of time looking at Furuno, Garmin, and Simrad for our electronics suite. We went into it not sure if we wanted to stay with the same manufacturer for everything, but in the end we chose to go exclusively with Furuno.
The Garmin had appeal for sure, but being still relatively new on the market (relative to Furuno I mean) we decided not to go with them.
Simrad also had appeal; the Broadband Radar & Structurescan in particular caught our eye but again these particular technologies were still in their infancy, at least in the recreational marine market.*
Although in today's world it is theoretically possible (and I'm sure many folks have had good success doing it) to mix electronics from different maunfacturers, we elected to go with one company to reduce and hopefully eliminate any interconnectivity issues.
Furuno was our choice because of its reputation for good solid design and workmanship. Once installed, we intend to keep this suite for a minimum of ten years, and the other options did not give us the confidence to be able to do that. Walking the docks in our cruising area (BC) we see a lot of Furuno radars, some ancient, on the commercial boats which says a lot. Those guys need reliability.
We went with the Navnet VX2, 4KW radar, fishfinder module, and Navpilot 500/511 combo. Many folks like the Navnet 3D but we liked the simplicity of the VX2. (Apparently it is Furuno's biggest seller).
Anyway, good luck with your quest; I don't think you could really go wrong with either of your choices.