It depends what you want.
I haven't actually bought the Salsa but I decided I didn't like it when I went to the store and played with the demo one. The Salsa is extremely strong. Like "numbs your hand after 30 seconds" strong. Mia is less buzzy as well. I really dislike that sort of thing. It also doesn't have as many speed settings IIRC.
I got the Mia and it is actually my favorite clit vibe. The vibrations are still fairly strong and it's quiet. I liked that it had 7 normal settings because it's kind of better for warming up rather than a super high setting right away like Salsa. It's like there is no room for foreplay if you bust out a Salsa? If you want to put Mia on the high setting first then you can do that but I like to keep it on the lower ones and increase the speed gradually. The USB charging is nice and it's super discrete. A friend came over to my apartment and thought I got new mascara when she saw it on my desk. If you take the cap off and leave it out then it just looks like a flashdrive. The waterproof is nice. Personally I thought that it was basically everything I wanted in a clit vibe look and function wise. It's my go-to vibe. And of course LELO has great warranties and such. I LOVE mine.
You have to press for 3 seconds to get onto the vibration patterns but after that you just press + to cycle through and I actually had no issues with it.
If you have a Clit of Steel/are a power queen then it's probably not for you. But for the sensitive or average user, you might like it a lot.