Raytheon/RayMarine works fine
I Installed a Ratheon ST4000 (before their 'plus' version) around 1995 in my 88 Catalina 30 TRBS/Wing Keel and it continues to still work fine after 10 years, never needed any service nor has ever failed me.The instrument head is in my Edson swivel pod on the pedestal, and the flux-gate compass is installed in the quarterberth sette seat's 'bulkhead' starboard side, just below the aft edge of the chart table.My only complaint is I wish the flux-gate compass wire was longer so I could have installed the compass under the draws in the hanging locker.The one thing I did to avoid problems which others were and might be having is to oversize the power wire to the instrument head to prevent any voltage drop. Remember to use the 3% voltage drop table recommendations for the round-trip length and then consider up sizing one more gauge (I went up the pedestal and came out via a hole I drilled therein).Regarding GPS, I have Raymarine's GPS/WAAS RayStar 120 Receiver with their ST50 'Navdata' instrument head in the cockpit with a PC running Raymarine's v 5.1 software at the nav station below.However, it sounds like you want portability, so I can only advise the ST4000+ instrument head can accept NMEA GPS input (I did it with mine via my old Loran), so you should be able to wire most portable units into it via the portable GPS's 'data cable'.hope this helps...