I agree with the rest of what you say above, of course, but to be honest, I wouldn't recommend even that.
In my opinion, you should avoid them
all.
It's relatively easy (given plenty of knowledge, understanding, judgment and due diligence!) to identify a signal service that has had a good few months of profit, but
it won't be the same one that's still making profits in three months' time, and there are reasons for that (which aren't trivially easy for the uninitiated to understand).
There are thousands of signal services out there and at any one time, out of those thousands, it follows that there will be a small number who happen, simply by the laws of chance, to have had a run of a few good consecutive months. But there's also selection bias at work, which predicates that those few are usually the ones you see advertising and promoting and being recommended most prominently, and therefore the ones your Google search will find (not to mention that they often also do "search-engine optimization" of their own, for their pages, to ensure that outcome).
Unfortunately, the fact that they happen just to have a few good months has very little (or "no") bearing at all on their chances of having a good few months again when you subscribe, because they had it by luck and "because someone has to", not by skill.
They're successful
marketers, in short - not successful traders.
And that's an additional "hidden reason" why it's so very common to join a "successful" signal service and for it all suddenly to turn sour as soon as you start paying for it. The bottom line, here, is that trying to make money by copying others is, for most people, most of the time, a pretty rotten idea.