I'm going to be the black sheep here. Agree on a 9.9, Zuke or Yamaha. However, after going from a tiller steer to console, I prefer the tiller. Tiller advantage is instant throttle control and steering. All you do is twist the throttle and you can turn lock to lock in a second. You can react way, way quicker than a Trollmaster and even wheel with spinner on it. I know because I have one. The tiller is more work in wind but you get significantly better boat control. You might have a sore shoulder at the end of a windy day. It also depends on how your boat is setup.....my old boat had a seat that worked perfectly. If you can't sit and steer, a tiller would get old. And don't forget vision, when running the tiller all the rods are in front of you, you see strikes much more often than sitting in the drivers seat. Oh and varying speeds can be done much more simply with a tiller than a Trollmaster. Console steer advantage is it's more comfortable. Trollmaster is nice, set and forget it but you get lazy and don't change speeds enough. Sitting in the captains chair is nice though.
What I will do on my next boat is this- put a tiller steer kicker on, but have a quick release bar to the main motor AND a Trollmaster ran to the console. That way, I can run the kicker via tiller handle when wanted. But, I can also use it from the console, I just have hook up the bar, trim it down and put it in gear from the back, then I can drive and control via the console if I want. I thought it was ridiculous but a buddy set up his 620 this way and it works awesome!
Beware of not buying a motor with power trim & tilt. Some motors, especially the 6hp models, often don't have this. That's fine on a calm day, but on a windy day they are just laid over on their side & on their tilt rod. They get beat up and bounced around terribly. Two boats ago I had a 8hp Nissan setup this way and I put in RAM setup to hold the kicker staitionary when traveling. Worked well but was one more thing. Good luck!