I think the future is contemporary ethernet. Top manufacturers are making radars and MFDs with this, and it's easy to add computers and black boxes.

NMEA2000 to me seems like 10-base-2 ethernet of the 1990's business networks. It used T's and a bus configuration and was simple. But it was a pain to wire reliably, and a bad connection on a T brought down everything. I dropped that 10-base-2 as soon as possible in about 1996. As such I can't get excited about it for anything bus network with T's where reliability is of utmost importance, even though I have not personally experienced any issues with NMEA2000 aside from shoddy T mounting. 

Currently in marine electronics, at least in my niche of commercial users, I sell quite a few computers with Nobeltec TimeZero and Olex and people are mostly interfacing their electronics to the computers with NMEA0183 and ethernet. The electronics are sensors such as radars, black box sounders, sounders, plotters, radios, GPS antennas, AIS, etc... Once in a while, people use the very nice Actisense NMEA2000 to USB converter but it's definitely a minority. 

In what we deal with for commercial boats, they'll have a few things connected with NMEA2000 because it's meant to work that way, and other things will use 0183 because it's simpler and more bullet proof. You can't get much more reliable than a simple cable between a sounder and computer if it's just sending depth/temperature/hardness sentences. These customers will avoid 0183 multiplexers and other gadgets... Keep it simple and reliable.  If you have a ton of data like from a multibeam sounder, you use ethernet since NMEA2000 is not capable of the data volume. Actisense makes optoisolated serial cables for 0183 for connecting devices that need that. Some 0183 devices like Hondex sounders and plotters are internally optoisolated and that makes 0183 very reliable and simple. These boaters will still get their job done if there is an electronics problem... They choose reliable electronics interconnected in a simpler but perhaps less convenient fashion. They might even have redundant equipment as well. Nobeltec has made ethernet very handy for interfacing with Furuno MFDs and black box devices.

As mentioned I sell Hondex plotters/sounders; they are 0183 only and are popular in Canada, New England, and various overseas locations mostly for commercial fishing.

0183 is also very simple to troubleshoot. I can use a laptop with a serial-USB converter and watch the dataflow using a terminal program. Some systems like TimeZero, Olex, and Hondex have diagnostic screens to view the data flowing in or out as well. It can easily be captured, reviewed, etc...

Ethernet can similarly monitored with a laptop and wireshark and a switch that supports port mirroring; normal IT investigative things marine electronics people are not familiar with yet.