Is the D300 Worth Buying??

I currently have a d5000. I found a great deal on a d300 with around 15 000 shutter actuations and seems to be in good condition. I am interested in the D300 for its better build quality, fps, autofocus, and better control layout. I am just wondering if I will lose anything from the D5000 i.e. dynamic range, high iso performance getting the D300.

Is the D300 still a good upgrade?

Any input would be much appreciated