Review: Nathan Intensity 2L hydration pack

4 mile run tonight while the sun was setting.
The rest of my pictures were deleted by an MP who tracked me down on a complaint that I was photographing the base. He took my iPhone, then viewed and deleted the pictures before writing me up. I wasn't even aware that I had been doing something wrong.
A very upsetting end to a nice run.
Anyhow, 12 miles to run down sometime this weekend. I'm feeling a little jaded right now but hopefully I'll get into the spirit soon.

Otherwise in the news, I received my Nathan Intensity 2L hydration pack! I took it on my short run tonight to work out the kinks before really needing it on longer distances.

Pros:
Didn't bounce.
Small and tight on my back but yet holds more than I even need to carry right now.
Easy to adjust - I think.
Easy to take apart and clean.
Key ring and strap so the keys don't bounce at all in the bag.
Mesh pocket holds my iPhone while I have it on speaker so I can hear music (because you can't wear headphones running on base).

Cons:
Bite valve was very stiff and I had a difficult time getting a sip and then pushing it back in to lock. This SUCKED. I tried using my fingers and my teeth. It is very difficult to pull out and in on top of having slick sweaty fingers.
I felt rubbing against a piece of plastic under one arm... I'm worried about chaffing and need to look at adjusting it differently if possible.
And lastly, the cords all seemed to loosen up as I ran and I had to keep adjusting them tighter. I am not sure if this is my problem or if the fabric is too slick. I'm really worried about this one because I'm not sure I can knot the cords in place because they'll stick out and rub against my arms I think.
Argh. I really do like this water pack.... It got GREAT reviews all over with only the mention of the bite valve problem. I think there have been complaints about the bladder but I'm wondering if I have an updated model because mine seemed secure. It does slosh, but didn't really move around or slouch - and I definitely didn't notice it beyond hearing water in it.
I'm just not sure if the issues are all me yet or if it's the Nathan design. It was kind of a love/hate run with it tonight and that has me a little worried. I am really, really not a big fan of hand carrying water though, so I'm going to really try to make this work.
I did get a good deal on mine: $69 on Amazon with no tax and no shipping (I got the last one sold by Amazon however). I couldn't find it anywhere local and online it's normally $85 plus possibly the tax/shipping on top!