While I was unimpressed with the app, I don't think your review is fair to the application. Download times were slower earlier today because everybody was downloading it at the same time. It took me less than a minute to download either file for phone or PC.
Using the map downloader, I was able to load Illinois, California, and Georgia in under an hour, probably more like 40 minutes. That's still a lot of time, but it seems like I won't have to do that again unless I need more states in the future. I was also using a card reader, which may not be an option for N91 users, but it certainly is an option for the rest of the s60 community. I have a feeling that's what contributed to the differences in our download time since it always takes longer to transfer information using the data cable. You also downloaded a version that isn't the the N91, which may not matter, but I have a feeling it does. Considering things like the lack of a memory card slot and the low resolution screen on the N91, I'm actually not surprised that it crashed on you at all.
Since I've been playing with it, I have yet to have the application crash at all, though the initial loading time was quite long. Now that I have the maps loaded, the application opens within 5 seconds (faster than the Java GoogleMaps) and finds the locations I search for instantly.
I don't like the application for the basic features it wants you to pay for, but I don't think it's fair to say its as buggy and unfinished as you described.