To answer your question its pretty simple:
1. When we fish for steelhead(migratory rainbow) we use a finesse technique which consists of long rods, light line and small hooks. Pound for pound steelhead are one of the strongest fighting fish we have in Ontario, even Canada for that matter. So as steelhead anglers we are challenging the extremes which consist of fishing for the biggest fish we can on the tiniest line we can get away with. (I still don't believe any guy fishes 8lbs + steelhead on 1lb test and actually gets them to shore). We also do it because once you get into it, the true addiction of steelheading is something that we will never grow out of, our addiction only gets more out of hand the older we get.
Now that's the reason why we steelhead fish, but when we compare it to salmon fishing its pretty easy to understand why we rather steelhead fish than salmon fish:
The reason why we don't enjoy salmon fishing nearly as much as steelhead fishing is because the salmon season is a poop show. All the clowns come out and since all they want to do is catch a fish with any means necessary to achieve this, they (as in about 80-90%) ultimately resort to snagging because it's the easiest way to catch salmon. It's disgusting, and really isn't a fun thing to watch. So we pretty much try and avoid it. Once the salmon season is over with the crowds go with them and it gives us more room to breath and be surrounded by serious anglers.
2. For the most part the order goes like this: Atlantic salmon come in first in early summer (although there aren't a lot), then it's chinook in mid-late august until about mid-october, in between the chinook the browns come in, around early september to mid to late november (have caught some in mid december though) and then the steelhead come in last in mid to late october and stay all winter till at the latest june. Often a cold october rain will push the steelhead to start coming up. If we don't get a mid-october week of cold and rainy weather, you can expect them to be in the rivers later in the month of october but for the most part mid to late october is when they start coming in.
Hope this helps
P.S. If anyone wants to prove me wrong about my statement of being able to land an 8lbs + chromer on 1lb line please contact me and show me your ways