Garg towers are only good when boosted and that’s the fact, unboosted doesn’t do enough demage on both low and high level. Boosted is realy good, everyone is using it if they win it in a war.
Snakes towers don’t have a boost but are good in my opinion. You won’t see many of them at the top bases but top players do use them, one, two, three maybe, if its placed right and combined with another towers it can be deadly as well.
So it is really up to you. I would suggest to have one or two high level snake tower but at certain point you will have to build and upgrade many garg towers and use them when are boosted - in this case you need quite a lot of them.
However, as snakes are not that essential but it is good to have one, two or three just in case, as garg towers will be only useful when you win them at war (and if your alliance is not able to prolong them you will have it for free only for a couple of days each month) I would suggest you to focus on skull towers which are the most essential tower through your whole gaming experience, you will want to have many of them.