1. The control is way too small (less than 1/2" in diameter with 5 functions)

2. The navigation sucks -
a. You can't choose a song directly w/o playing a folder and then advance to the song you want.
b. You can't back out of a folder w/o going through menu | folder option | 1st folder | next/prev folder...
c. Only 2/3 functions of the tiny control wheel is available for navigation.

3. They want you to buy additional battery for $50 instead of using standard batteries.

4. The control wheel and play buttons are completely hidden when the unit is in the case so you have to take the unit out before you can control it.

5. The USB 2.0 and USB charging support are nice. However, you can't use the player in the USB charging mode.

I purchased this device to use while exercising, not to store my entire music collection. The 512MB flash memory gives me enough space for 5 or 6 albums recorded at 128kbps, which provides fine fidelity. If you want a large storage volume and are not worried about moving parts, take your chances with a hard-disk drive unit.

The earphones are functional if not particularly comfortable. The sports armband is secure and the lithium battery arrived charged and ready to use. The control buttons are simple and easy to use and the LCD display is easily read even with my tired, old eyes. The software provided works well with my Windows XP operating system and moving files back and forth is very simple.

My only complaint is that the X-Trainer wants to replay album tracks by the title of the song rather than the track number. I'm sure there must be a simple solution for this problem but the instruction manual, provided on the CD, is not very helpful. I've tried to find a solution to this small annoyance but to no avail. A simple if cumbersome work-around is to manually retitle each track using an alpha prefix (a_NAME, b_NAME, c_NAME, etc.) in order to hear tracks in the order I want.

Apart from this one small problem, I give the X-Trainer a strong recommendation to musically-inclined exercise buffs!