The best device for LDing and DR

I have visited those two websites but I cannot decide which device would be better to improve dream recall and possibly help in LDing.
now-zen.com/
sleeptracker.com/
Thank you in advance for all replies.

Well… I don´t think any of these devices would help you in LDing… I can´t imagine how!

For improving dream recall:
The sleeptracker wakes you up right after a REM period. That means, you can recall at least your last dream more easily, because the dream happened right before you awoke.
I don´t know if the Zen Alarm clock can help you to improve your dream recall at all.

Jack05