So I've tested this on the EU and the US servers now, which is approximately 4 rounds in total, so I've got a good grasp of the game play objective and good strategies for winning.
Overall the map seems fairly well balanced, although there's no real choke points unless Red team either deploy an uber or build up a sentry farm; generally if someone in defense deploys a very successful uber at the beginning, their entire team will end up spawn camping Blue quite easily.
The only times Blue really got stuck were as I said when Red deployed an uber or built up several sentries, but this is often the case and since we didn't get many counter ubers, it's understandable why we might not have succeeded.
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Visually, the map doesn't look all that attractive, which is understandable given that it's in its alpha phase still; the problem is that it's too plain, the majority of the map is you running outside with a set path, and a few buildings, some of which can be used to cut corners, but no real flanks or areas that are outside of the main battle zones (although this is a relatively fresh game mode and those may be unnecessary for all we know)
There is also that irritating glitch with the lighting, which I understand you will be fixing, relating to the cubemaps, resulting in entities or objects that make use of them appear white.
The HUD is very nice though, circular icons definitely look nicer over the rounded rectangular default set, and adding the briefcase to the icons (I'm assuming this was custom) was a very nice touch, indeed.
So, visually, there is room for improvement, and perhaps there is room for extra areas in which Blue and Red teams can attempt to fight in, but overall the game is very nicely balanced and the HUD icons are very nice.
Good work!