I will say it, the 450 is nowhere near as durable as the mx500/600/650/700/800/850 and 980 designs. A drop on hard flooring services has about a 50% chance of cracking the case and having the plastic screen protector fall out.

I would heavily recommend going to the mx780 over the 450 (for the extra $50), having the power of computer programmability alone is worth it (not sure how I'd rate the 780's durability it feels better built then the 450...but I don't have enough in the field to comment yet).