We have had good luck with the Seresto brand and it was recommended by quite a few in the field community. It is for fleas and ticks but not mosquitos (as far as I know). The only problem we had was that one dog was grabbing the other dog’s Seresto collar and eventually removing it. Then she ran off with it and it took quite some time to find.
Seresto has been in the news recently because of lawsuits or claims that it injured some dogs. I haven’t read the articles yet but in general, yes, whether your using a collar or the gel flea and tick repellant, you are exposing your pet to pesticides. That is what it is. We are in the woods and brush so often that we have to use something.
I have heard that the Bravecto gel is particularly problematic, I will have to look closer at the Seresto claims.
I've been using Seresto collars for 2 years now. My first experience was not good, as after a few days of my dog wearing it, he must have got into the ticks something fierce because I pulled 10 or so off of him. They were on his snout and head which leads me to believe, as good as the collars are said to be, if your dog sticks its nose somewhere he shouldn't then its hard to prevent them.
What that said, since that day, I have not seen a single tick on him and in our area they are very prevalent. So maybe, I didn't have it on long enough for the collar to work its magic and spread the repellent through the dogs coat, or maybe the snout is susceptible to ticks because dogs stick there noses into brush and thickets all the time.
I will say, I do double prevention, I use the collars during peak season as well as monthly Nexguard treatments.