And you are right about the summons not being strong enough. I was irritaded with the fact that even with alot invested in spirit control they would still have a 35-40% chance to escape. And the fetishes also cost way too much.
BTW, do you know how the summon escape mechanics work in dragonfall/dms and and how different they are from pnp? Is there randomness in what they do after escaping control? In DF sometimes they disappear, others they fight you or your enemies. I've looked around for this but never really found anything. And the game doesn't make things easier. They could've at least had this things explained in the help menu or better yet, a combat log.
Well, for starters, there are no fetishes for summoning in the original rules. You might need some for roleplaying reasons (like needing some sand to summon an earth spirit, maybe), but that is really left to you/the GM.
Summoning is a normal spell casting check (just using the Summoning instead of Spellcasting skill), which you have to succeed in in order to summon something. Then comes a drain check to see if the casting hurt you. In SR, casting is simply a demanding action - the stronger the spell, the more demanding the casting will be on your mind and body. Cast something too much for your character and the character might collapse. It is the most perfect balancing. Easy spells can be cast pretty much without limit (except failing badly at the drain check), while very strong spells will almost certainly hurt a caster who is not a master - which might be acceptable, if it would kill the opponent, for example. I really don't like that SR:R has changed the damage mechanics so much. With just an HP bar, the described mechanic would not work too well.
So far, summoning is normal spellcasting.
Now, at least in 4th edition, the number of leftover successes in the summoning test determine how many commands you can give to the summoned spirit. Failure in casting when we played was always a GM decision. In some cases, no spirit would appear at all (which is I think default by the ruleset), in some, the spirit would just go on a rampage, etc. In all cases, you would still have to do a drain check, as the try alone is the demanding thing, not succeeding. But even if you succeed, the GM controls the spirit, so you better give logical, clear commands
There is no real "breaking free" for summoned spirits. Just the normal "leaving" when the command is done. Of course, when the caster dies or becomes unconscious while a spirit is summoned, all kinds of stuff could happen (again, GM decision, mostly).
Of course, there are things like friendly spirits (who just happen to like you - giving more or unlimited commands), hostile spirits, bound spirits, etc.