I've been using CDFinder for years and had been pretty happy with it. After reading reviews here on MacUpdate I was hesitant to update to NeoFinder because of claims of slowdowns and bloat.
Today, I backed up everything from CDFInder 5.x and then updated to NeoFinder 6.2 and I'm VERY glad I did. NeoFinder 6.2 starts up faster, searches faster and the interface now looks just like the Mac OS interface and behaves the same as well which is awesome.
There has been some extras added to NeoFinder that I have no use for currently like the map/GeoFinder thing, but I was able to turn that off with one click of a button. I also would prefer that there was an option to turn off the Dock icon animation it does when it runs as well. It doesn't appear to slow anything down, but I find it distracting and want to be able to turn that off. There also doesn't appear to be a way to turn off checking for updates when it starts and that's annoying.
The update from CDFinder 5.x to NeoFinder 6.2 was absolutely seamless. It found the database without any user interaction and was available literally instantly without taking time to "update" the database, etc. Also, it appears that no data was lost and it seem to respect my old settings as well. I'm not sure I've ever had such a seamless experience updating a app like this that relies on a database.
I also really love how I can still double-click on a hard drive catalog and it will open in a new window if I want it to. I was nervous that after updating the developer was going to jump on the one-window-interface-only bandwagon that Apple has errantly done with iTunes 11, etc. -- So that was a relief that the dev smartly allows you to do what YOU want to do instead of forcing you into a "trend" that may or may not hurt your productivity.
The Smart Folders get a little clunky while waiting to populate the list and I at first was worried that the app was stalling, but then the list popped up. Considering the hundreds of thousands (maybe millions?) of files it sorted through to show the results, it was quick to say the least. The only complaint I have is it might be a good idea if the smart folder icon shows a spinning icon or something while it's processing so you know it's working. Or just an option to have that would be nice.
Scrolling around CDFinder was pretty smooth and played nice with the indispensable Smart Scroll prefpane I use. But NeoFinder is even smoother, faster and better at scrolling than before so that's another great bonus of updating.
I also tested updating an external FW800 G-Drive Mini's catalog and found that it respected most of my old settings. It added the option of adding thumbnails to images, but I decided that I did want that and allowed it. It went through about 75,000+ items with a huge percentage of images this way in about 7 minutes (which was fast as heck for how many thumbnails it processed). After it was done, I was really impressed with how fast the larger thumbnails popping up the the Get Info window on the right as I scrolled down the images with the down arrow key. Also after that intial huge scan that created all the image thumbnails, I added a few more items to the external hard drive and a subsquent "update" of the catalog only took about 13 seconds which seems to be on par with how fast the older CDFinder updated the drive but without the added responsibility of checking the thumbnails. So NeoFinder did great there as well.
Although my fans blasted while doing the thumbnail update (as it should when speedily processing so many images), my MBP i7 didn't seem to slow down while this was going on even while running many other apps, etc.. There was a lot of old images that I know were probably corrupt and wondered if NeoFinder would choke and crash on them, but it all went smooth which is definitely a testament to it's stability in that regard.
Unfortuantely, while scanning and going through the tens of thousands of images and adding thumbnails for each, it did eat up a LOT of the RAM (I have 8GB of RAM) on my laptop, but I expected it to that as well to keep the process speedy. The major problem is it didn't release the RAM memory after it was done which was quite a bummer (but hopefully this will be resolved in future updates) or if it did, it released very little of it over time. YMMV with this, I'm using Mac OS 10.6.8, so it might release the RAM better with 10.7.x or 10.8.x. -- But, for me, it ate up RAM and didn't let it go.
All in all, I think this developer did an absolutely fantastic update and I highly recommend this update and NeoFinder in general. I never tested with the previous versions of NeoFinder before 6.2, so it may be that I'm using a version that has many previous bugs fixed.
The only glaring downside is at least with Mac OS 10.6.8 and NeoFinder 6.2 and indexing/cataloging a lot of image thumbnails, it ate up RAM and didn't release it when it was done, nor after I quit NeoFinder. So the dev needs to fix that before I can rate the stability higher. I don't want to have to run "purge" in Terminal or restart the laptop after using NeoFinder to update lots of image thumbnails on catalogs in order to keep my RAM free.