Earlier this year we purchased a Streetwalker and a Streetwalker Pro. My wife usually uses the Streetwalker whilst I use the Streetwalker pro.
I carry a Canon 5D mkii, Canon 70-200 F2.8L ISii, 14-40 F4L, Sigma 150mm F2.8 Macro, Canon 1.4x Teleconvertor, Filters in Clik Elite pouch, headlight, cloth etc.
I find the pack very comfortable to wear for extended periods and not too hot (We live in the Tropics of Northern Australia).
I like the hideaway waist strap which makes the pack very comfortable for longer walks.
Where the Pro stands out from the std Streetwalker is the depth of the pack, this allows me to stand my shorter lens, including the Sigma 150mm Macro, on end. The Canon 17-40 has the hood fitted and stands on end with ease. I still have room for another smaller lens such as a prime portrait lens such as a 85mm F1.4.
My wife like the depth of the Pro so she can carry her wallet on edge as apposed to carrying it laying down jammed against a lens!
The D rings on the shoulder straps are great for hanging the camera off, clipping a cleaning cloth to. There are small pouches in the shoulder straps which you could hold spare cards although they would be exposed to the moisture should it rain.
The rain cover looks like it would do the job nicely but I have never used it to date.
Included Tripod straps work very well but I stick 2 of the tripod legs in the bottom zip compartment rather than use the hideaway tripod pouch as I find the pouch puts the tripod too low and doesn't balance that well.

Advantages: More depth than the std Streetwalker.
Very comfortable to carry for extended periods.
Plenty of space.
Very well constructed.
Lockable main compartment.
Easily fits cary on size requirements. Fits overhead lockers no problem.

Disadvantages: When Tripod pouch is used the pack feels unbalanced. It is fine if I use the bottom zippered compartment