Looking for a new 18 footer, tossing up with the above 3 mentioned with a 150hp motor.
Which would you go with and what would be your choice motor?

I'm a little biased but I love my 2001 18'6" Triton and would not hesitate to buy another one in a heartbeat especially with a Merc. But that's just me.

Of course I'm biased, my Skeeter ZX190 has been a great boat with very few issues.
All three will be good boats.
1. Go with a 175. A 150 will underpower a heavily loaded boat. Full fuel, full livewells, two people and lots of tackle will bog down a 150. The 175s usually have a better gear ratio. I have not heard any bad reports on the Yamaha 175 SHO. Skeeter will be Yamaha only.
2. Look at all three and see which lay out you like. Check for where you will put electronics. If it comes equipped it will mostly likely be 7" screens. If you plan to upgrade check if bigger will fit.
3. Check the dealer reputation. Even a great boat can turn into a lousy experience if the dealer is bad.