What is the (mechanical) idea behind Companion sprites?
Their basic function seems to be sitting beside you and waiting for a chance to prevent damage to you.
Problem is without cybercombat or hacking skill they don't have any active role in combat and without a reason to ever attack the sprite it's high firewall is wasted. Same for basically any other stat, because both powers don't involve any stat besides a required initiative score of at least 10 for Bodyguard (and beating a 10 with 4d6+2 for a level 1 sprite isn't that hard).
Additonally Shield is badly worded: the first sentence makes it sound like an automatic ability not needing a task spend (which i would assume to be unintentional), the second one ignores the possibility of more than one active companion sprite ("[...] they may redirect a single box of damage to (one of) their companion sprite(s)" seems like the better wording, unless of course stacking companions is intended. Which would be very overpowered...)
Either way, bottom line is: There is barely any reason to compile a companion sprite above level 1 because they basically only exist to be sacrificed. The only thing that matters is the number of tasks for shielding (unless automatic shielding is intended, then even these are completely optional).
So... let's compile, register and re- re- re- register a level 1 companion for the 9 tasks needed to take 8 points of fading (on a monitor of 9) to have 1 task left to throw them at an incoming attack. Sounds... very strange.
And speaking of strange... what's about their great form power? Is it intended to be more useful to your decker friend as it can't actually heal the technomancer but only other devices/personas? And did i miss any restriction on registering a compiled great form sprite? Would that cause x2 or x4 net hits fading? Not that is matters much in this case because again i get most bang for the buck out of a level 1 one. At least there is a bonus related to the sprite's level here, but that "low level/high number of tasks"-sprite still is the most beneficial one, being able to do all the things mentioned before and to sacrifice itself to heal some other persona/device completely and prevent all further damage for the combat turn.