I'm with Bernie 100% in the way he described whether or not to get the Auto Pilot + Radar option when plonking down $100K+. I had to make a choice on this when we bought our R-25. I spent several hours posting the same question here and the overwhelming response was "get it".
Let me make a point... you're out one morning and visibility is very clear for miles. After some hours of cruising you find there's fog ahead and directly in your way. You have no RADAR and so you slow down such that you can stop in half the distance you can safely see. You simply are relying on other boats with RADAR for seeing you and also hope they have also slowed down as you have. The boat with the RADAR is probably feeling at ease knowing they can see through the fog with their RADAR whereas you are feeling very apprehensive. Having RADAR will make life a lot less stressful in this situation. The RADAR will have features that allow you to setup an area around your boat such that if another boat is detected entering this area or is within this area an alert will be sounded... its called SENTRY mode and provides a "guard zone" around your boat. Only yesterday I was experimenting with this feature in clear weather and I can tell you, it does work.
Mind you, a large wave occurring within your SENTRY collision zone or for that matter, a large dorsal fin of a killer whale would/might also cause the alarm to sound as the RADAR would/will conceivable detect this as an object. In fact I would venture to say, very rough weather with big waves and fog is a dangerous combination to encounter -- even with having RADAR.
Of course, if you are ever caught out on the water and darkness descends having RADAR would be a BIG plus.
Auto Pilot is a real blessing and removes a great deal of dedicated helmsmanship steering the boat on long straight portions cruising. As others have said, you can briefly leave the helm to tend to other things while the Auto Pilot steers the boat. I find Auto Pilot is a very nice feature in rough wavy waters. Steering manually is a constant back and forth with the wheel for keeping your course heading and this over time is very tiring. With Auto Pilot all of this tiredness and the effort on the wheel adjustment goes away. The Auto Pilot does a wonderful job IMO. One other feature I truly like that requires Garmin's Chart Plotter software and the Auto Pilot combo is the ability to plot a Safe Course to your destination. Once this is set and you engage the Auto Pilot -- then presto, the boat will be guided safely along the course line. I use this feature a lot in my PNW area.
So, if you are already spending $100K, $150K, or $180K I would say Auto Pilot & RADAR is a MUST have option. You will not regret it. I know I haven't.
Oh... and one last point or two...
1)
If you have RADAR do not spin it up within your marina as it can harm humans close by... (as stated in my User's Manual)
2)
As we are all responsible for avoiding collisions on the water using all means possible, then if you have RADAR you should be using it to comply with this.