It's legit and it hasn't been scammy, however it's incredibly buggy and poorly designed. Right now it can't start at all. It sometimes just breaks. That is horrible if your money is relying on this tool working properly on time. Also the UI is not great, especially for gas fees - sometimes I've had a transaction be reverted and it was completely unclear that this was even possible; I constantly had to use "custom" transaction speed and look up gas fees from a 3rd party website because the in-built tools weren't good enough. I'd recommend using a different wallet if possible - for example, Phantom is good. (Also there was a time where I lost the opportunity to earn a few thousand dollars since I was minting NFTs very slowly, because of Metamask on mobile acting very badly under poor network conditions, but I cannot honestly blame them for that - most software isn't designed and well tested for that. 95% of the fault was mine, for not foreseeing that most software gets buggy/bad with unreliable network.)