I played this quite a bit, all things considered, during a relatively short period a few years ago. It was pretty fun and charming, to be honest, but... There's basically no single-player (while I understand games don't need to focus on having a campaign, it's a trend I really dislike), and there are microtransactions. The usual AAA bullshit, sadly. I also didn't have friends to play with. Everything would be harder for me to forgive if it was regular military shooter, but its PVZ aspect makes it more unique.
There's not much of a player base now, so I can't recommend it at all. The sequel may be better from what I read, but I have yet to try it out.