Welcome, Tony! I'm in the same boat myself, as I've recently been researching/shopping/riding dual sport-type hybrids for over a month now with the intention of investing in my first REAL bike. I'm still a newbie myself, so consider my advice as you see fit. Hopefully someone more knowledgeable will chime in.

The first thing that jumps out at me about your list is the fact that you're comparing the Giant Roam 1 to the Trek 8.4 and the Cannondale SL 5 - both of which are probably $200 more than the Roam 1. Have you considered the Giant Roam 0? The only reason I mention it is because it's more closely comparable to the other two models, and in the same price range.

My first visit to my local bike shop, I was looking at the Trek FX models. After seeing them in person, I felt I'd be better off with a Trek DS as the FX looked flimsy to me... almost like a flat bar road bike. Don't get me wrong, the FX is a great looking bike and MUCH lighter than what I'm looking at now - I just fear it may not be durable enough for riding loose trails, hopping curbs, etc. The salesman directed me to the DS model instead, but also recommended the Giant Roam (both the 1 and the 0) stating that I'd be getting more for my $ with the Roam than a similarly priced DS model. Not sure what prices are like in your area, but the Roam 0 is a little less expensive than the DS 8.4, and they're quite comparable as far as features and components.

As for the Cannondale, you're getting a better suspension fork, but I find it's at the price of lesser components compared to the others. I've sort of written off Cannondale in my search if only for price. I just think you can stretch your dollar better with other brands.

Personally, the Giant Roam 0 is at the top of my list right now. However, if you're not considering the Roam 0 and are limited to the three models that you've mentioned, I'd probably go with the Trek DS 8.4.