Woot.com had a refurb Sansa Fuse 4g, and it looked like it would do what I want--big enough for a decent amount of music, the ability to use micro SD cards to add to its capacity, and the ability to appear as a mass storage device (meaning it acts like another hard drive) so I can use it with Linux without jumping through hoops. I much prefer just dragging and dropping files to "managing" my music. It is possible to delete files without using a computer, unlike the iPod Touch, and I can shuffle podcasts on it with the memory cards, leaving the player in the car full time.
Sound quality is fine, the included earbuds are better than the ones from the dollar store, but not as good as Apple or Sony, and the interface is decent, very similar to my wife's iPod. The Fuze has an FM radio, but with very limited range. Charges via USB using a proprietary cable. When using a computer to charge, the player switches to file transfer mode and will not play music. When using an external USB charger, you can still listen.
Another oddity is that files put on the player using Windows Media are not visible when looking in hard drive mode, and vice versa. There are several not-so-good songs included at purchase, and I didn't spot them when I loaded music the first time.
The biggest flaw is how it handles bad .mp3 files. Many players can be picky about what bitrates they can handle, skipping songs that they cannot play. When the Fuze gets to a bad file, it either reboots or crashes before the song can even start. Worse, it backs up several spots on the playlist so when you start it will hit the bad song again. If you are in random mode you have to remember to check the "next up" display (not enabled by default) on the song BEFORE the crash, so you can delete the offending song. While the Fuze has the ability to delete songs without needing a computer, it will only delete the currently playing song--so if a song won't pay, you still need the computer to delete it. This behavior meant that wioutout a workaround, it would be entirely unsuitable for my car.
This flaw was almost enough for me to send it back. I suspected (correctly as it turned out) a bitrate problem since both the problem songs were variable bitrate. I found MP3 Diags, a program that can find and fix many different problems on mp3 files. Even better, it can batch process, meaning I could run all my mp3's through it to find and fix in batches. On both of the bad files, the Xing headers were wrong, and MP3 Diags was able to fix them. I have since let the Fuze run for several hours, and it has not crashed or locked up once.
MP3 diags is free software available for both Linux and Windows. it could use some improvement of the user interface, and some automation but it isn't a program you will use daily so that is a minor complaint--It is miles better than any other way I could find of dealing with my problem with the Fuze.
Although the Fuze seems to be working fine now, it took way too much time and trouble to find and fix the problem. On the other hand, this may be unique to my player, since I didn't find a similar issue on the Internet. Overall, a C+--the price makes up slightly for the hassle.