No weaknesses unless you consider price tag a weakness.
This marker is amazing. First of all it's completely customizable - as in you can get in in any color, you can get it with 2X frame, single frame, left feed, right feed, center feed, brass barell, nickel barrel, aluminum lapco barrel, blah, blah, blah. If you got the coin, Palmer can deliver.
Aside from being one of the most accurate paintball guns I've ever shot (only my Typhoon compares favorably), it is also rock solid and light. It runs great on CO2 and I play in NJ where the winters aren't always conducive to paintball playing on CO2.
The only conceivable weakness might be the price but when you consider the bang for the buck, it's still the best deal in the paintballing world.
My final recommendation is that if you're in the market for a higher end pneumatic then you cannot go wrong with a Blazer. As a matter of fact you will go wrong if you DON'T buy a Blazer.