I had two of them, started with one and had the same model G2 that crashed doing a software update and it was replaced by a G3 instead of reflashing the memory last year.
The Helix 7 models that don't have N in their model names are not Networkable (has to be G3N to network). That excludes them from supporting Ethernet accessories or sharing data.
The included transducer is the same Compact SI size as the older generation Helix 7's so its image quality is not as good as the larger units with larger transducers. Longer Imaging piezo lengths create a thinner Imaging pulse and sharper images.
Additionally the Compact SI transducers (regular and MEGA) don't have a Down Imaging piezo so they create Composite DI views by blending the two SI pulses==not a sharp as a dedicated DI piezo.
The processer is less than the larger units which reduces the image quality somewhat.
It has HW CHIRP 2D sonar via a Low-Q CHIRP rated piezo in the 140-240 kHz range, same as the larger units,
It has two Imaging frequencies, 455 kHz and 1.2 MKz single frequency or CHIRPed.
It's still a decent unit though--just depends on what you compare it to.
If any are left in stock anywhere, they should be near close-out sales since the forth generation is due out soon.