Hey Daamu,
A mate has the Dragon Fly 7, the only downsides IMO are because it is an entry level sounder it doesn't have:
1. Touch screen
2. The networking abilities (NMEA0183 & 2000) like the MFD's and,
3. Because of number 2, you can't dual transducers and add on sidevision.
However, for the price it is a really neat little unit. We have only used it in Moreton Bay.
I can't comment on the Lowrance sorry, but there might be a Humminbird equivalent you could look into.
Regards,