Well I went ahead and flashed my Hero to Fresh's 2.0d this week end and I have to say it truly made my phone worth hanging on to. Here is what I have noticed so far:
Blue Tooth File Transfers!! - I never understood why a phone that costs this much was unable to do this.. I mean com on, my daughters Instinct s30 was able to right out of the box..
Less Laggy - I put my newly flashed phone next to my wife's Hero and there was a noticeable difference in apps coming open and touch response. There were times before the flash that I missed phone calls because the lock scree wouldn't work fast enough after I pulled it from my pocket.
Apps Reinstall - I did see in the "My Downloads" section of market all the programs that I had on the phone, however I did not install all of them before closing out of the market. Now they are not listed anymore. No problem I didn't want most of them anyway. All data that I had (pics, ringtones, and such) were still there. I guess the reset and ext wipe are in a different place on the SC card.
Wireless Tethering - It just works.. I hadn't tried it till Sunday and my daughter wanted to scoot around the internet so she started the program and - poof - it worked.
Battery Life - I noticed a great improvement in battery life when it is not searching for service. I think on Saturday the battery lasted for over 12 hours with me fiddling with it most of the day. Take that for what it's worth.
Over all impression - Fresh rocks! He has defiantly made the wait for 2.1 easer to deal with. Not that I am going to flash to stock until I see it has been rooted

For those that haven't downloaded it yet, I highly recommend it!
Oh one last thing - If you are like me and thought that you had to do a factory restore and ext partition wipe THEN copy the flash file to the phone.. DON'T if you restart your phone after the factory restore and before the flash you will have to re wipe and flash before it will work. Also when it comes up the first time it WILL take a while.. relax this is normal, go drink some tea and have a sandwich it will be ready by the time your finished with it.