My boat came with some very dated Raymarine instruments. Three years ago it was time to replace them and I spend a fair bit of time researching and then talking with vendors at the Annapolis show. The goal was all new instruments and a new chart plotter that would work with our existing Simrad wheel pilot.
At that time Simrad and B&G were much more expensive. B&G had a lot of features for racers that didn't apply to us as bay cruisers.
When I talked with Raymarine they admitted they were not fully NMEA2000 compatible. That was a BIG negative. Garmin was. I'd also had a negative customer service experience with my old Ray gear.
Playing with both systems I found the Garmin chart plotter and displays easier to use and more intuitive. For most things you really don't need a manual.
Over three seasons our Garmin gear hasn't had a problem. A friend who installed a complete Raymarine system on his boat at the same time has had numerous system and wheel pilot problems. His display has had to go in numerous time for warranty work. So often that he bought a second display so he'd have one working unit while the other was in for service
Another issue - updated charts are free downloads from Garmin. Raymarine charges for them (a couple of hundred).
I'm replacing our original four inch display with a seven this season (441s & 741xs). The original plan was to mount the 441 below when I upgraded to the larger display. Instead the 441 will go onto another boat since the 741xs has wireless built in. It will work with Apple or Android tablets and allows you to set way points and do all your route planning from the tablet. In our case a 10 inch Galaxy we already own. And to correct a previous post the wireless is a local WiFi network; it doesn't require a cellular signal to work.
An important feature to look for is the ability to adjust chart resolution. On the Garmins I can adjust how much detail I want to see at various zoom levels and it really comes in handy. Another handy feature is the ability with a couple of button presses to see historical data on any of the displays. Want to know how much the wind has built through the day or how much the barometer is dropping? A couple of button presses will get you there.
Finally if you're reasonably tech savvy you can install one of these systems.