lms-334 or lms-339?

[fish2live]

i am going to buy one of these two finder/gps combos. the lms-334 has 2500 peak to peak with a 200 khz transducer and the lms-339 has 4000 peak to peak with a 200/50 khz transducer. i fish a max depth of 50 ftand may be running planer boards a little. in depths under 50ft will the extra power make a difference? will it give better bottom definition? is the 200/50 transducer something that the average fisherman would want? pro's and con's

thanks

steve