The SI unit can 'save your bacon'....if you learn to use it properly. Last Friday I had a sandbass guide trip and wasn't doing too good (about 12 in the box). Ernest and Jason even called me in on a school they were fishing, but it fizzled out by the time I got there. Then using my SI, I was able to locate a school of big sandys and in an hour we just about limited out.
And Ernest is a pretty good teacher on the SI if you're just learning.