Sold my 301 to get a 305. Here's a brief overview of what I've found so far:
1]Initial satellite lock-on is NO FASTER than the 301. But...
2]Once the satellites are locked, the device seems to hold them MUCH better than the 301. I am pretty confident that this is even more accurate than the 301 (which I thought was pretty good) at reading distance. I'll have to wait 'til mid-summer before I can make a judgement about lock-on under dense tree canopies.
3]The unit is more comfortable (both the watch and the strap) than the 301, but nothing dramatic here.
4]HR lock on is FANTASTIC. The 301 was only so-so. Once this thing grabs the signal from the strap, it DOES NOT let go. It has neither read erroneous numbers, nor just "blipped out" with no reading at all a single time yet and I've run a couple hundred miles with it so far.
5]The software in the watch device is MARKEDLY better than the 301. For example, you can alter ANY of the three data screens any way you like. Another thing I found out today is that you can scroll around various screens while in the middle of an interval workout. Pretty cool.
Overall, I think it's a winner. Whether you find it worth the $$ is your personal matter.
Hope this helps anyone who is interested.