I first had a Dakine heli pro but I diliked to have the board horizontal; seemd bulky to me while traversing steep terrain and I had the feeling that my balance was disturbed by the wind. I thus got a Deuter Tourride (vertical). Unless you don't have to walk downhill, I found the vertical carrying more comfortable. But this seems to be a very personal preference.
Which system ever you're going to choose, I'd check if there are features like pole holder and separate compartments to store/fix shovel and probe - when you do short pow off the resort and only want carry the basic avy equipent, the bagpack is otherwise empty and you're glad if the stuff is fixed in compartments and won't throw to and fro.
And yes, I always carry at least shovel and probe with me, even if only doing resort pow. We have people getting cought in avalanches in our little resort every year (mostly at days, when we decided that it's too risky to go off the tracks
) I remember an instructor saying: the avy isn't aware of that it isn't supposed to come here
Some resorts are very militant about demanding that you remove your pack and hang onto it when riding the lift. Taking the thing on and off gets pretty old!
there's a good reason for that: some weeks ago, we had a woman getting cought with her bagpack while trying to get off the chairlift, was carried away and fell 7m. Died of head injury.