new sledder
I have ridden most all manufacturers 600cc+ machines. I love (like we all do) the power of 700-800cc machines. BUT, I take my 600 Shift every time, unless someone talks smack and wants to dragrace up beat down hills, then I bring my sons older Gen2 136 800 Indydan/EricW/SW machine that they were kind enough to build for us. That 'ol beater will stretch your arms out. When its deep and fluffy, I take my 155 Shift. As an "entry" level, economic sled, it def. gets the job done and didn't cost $10k! You might not get there first, but you WILL get there. Reliable and a decent platform to mod if you need more. I didn't see where you stated your weight and height. If you are a 200 pounds or more,go bigger.
p.s. I am a para-sledder btw. I rarely get stuck no matter the terrain.