I have a set of both. four echo devices and three gh devices. For my use, I mainly use alexa. use gh only as a backup and troubleshooter. I hate having to say hey google. just like I hate saying amazon as a wakeup word. at least with amazon you have several choices.
I have several devices that does not work with google. also google tends to be hard of hearing. I sometimes wonder if it is like me when I am in stores and the clerks keep bothering me - selective hearing (play deaf).
this is not to say google is all bad. It does have better speakers on their devices. I like the home hub. it does not have the ads the alexa version has and it makes a better bedside clock since it does not have a camera.
I use the gh as a trouble shooter, at times when alexa says to check connections, I immediately ask gh. if it does do the command, then the problem is with alexa. If it also does not work, then it is easier to determine the next stop.
If you have your own music library, it is easier for alexa to play it than google from your pc. to be honest, not even sure if google can play a local library. One thing, gh cannot read your emails while alexa can. for me, that is very important.
If you ask a lot of questions, then maybe google home is for you. but that gets old so if that is the reason you got it, then it will gather dust after a while.
finally, both devices are constantly being updated, I think you would not go wrong with either. you can find all kinds of info about both and comparing both doing an online search. just type alexa vs google home in your search box.