Not only for the sheer fact flash players will never skip and are much less likely to get damaged(since there are no moving parts/read heads) but perhaps more importantly because the flash players use STANDARD batteries!
When you are out mountain biking or up snowboarding just how convenient is it to find an AC adapter and recharge? My guess would be not nearly as easy as it would be to simply swap in a fresh AAA battery.
At the moment the Sandisk Sensa seems like the best deal going(I'm always leary of "vaporware" in the mp3 world... waited far too long for products that should be released anytime now). My advice would be to buy the 1gb version now @$133 and get a dirt cheap 512mb SD card for just over $20 until the 2gb versions drop some more. Recently Dell had them for under $125(after rebate) but we both know they will drop like a rock soon. They always do.
I hope the Lexar product does arrive soon and live up to the hype but in my experience after having owned at least a dozen mp3 players... an mp3 player in the hand is a great deal better than one on waiting list. I'm happy with my Sensa for now.
I've always favored flash players for their non-skip design which fits my life style. (extreme sports; moto-cross, mountain biking, snowboarding, sportbikes {wheelies} etc etc). But they do lack memory capacity. Now we have 2GB players out iAudio's and the new iAudio U2 in white and new players with removable memory; New Sandisk & the super pimpy Lexar LDP-800 if it ever decides to hit the market?? Most online dealers have it in there items for sale, but of course, 'Not Yet Available'.
Memory these days is exploding in size with SD cards etc, we're now at 2GB cards... Give it a year or so and they'll have 5GB cards especially since the digital camera market is exploding. The new Lexar (when it debuts) will have 1GB which may arrive with 2GB standard memory, PLUS removable SD in a compact size and built in FM transmitter. This would obviously be a better purchase vs. a Micro Disc player (RIO Carbon, iPOd mini). Opinions??

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