Missed this post when I replied to another asking basically the same thing yesterday, but yes I have. I went for the TTartisan 25mm f/2 in the end over the Meike lens, largely for the fact that the TTartisan lens has a clicked aperture ring, while the Meike's doesn't click. Cost me £69 from Amazon, and it's great. Tiny, all metal, feels very solid. Like I've said on another post the corners are horrific wide open, it has massive vignetting, barrel distortion and flares loads if you point it at a bright light but it's loads of fun to shoot with and the images from it have a lovely vintage quality. The IQ improves a lot if you stop down to f2,8 and by f4 it's pretty sharp apart from the extreme corners. Shooting manually is fun, it makes you slow down and work for your shots a bit more.
If you stretch to over £100 I believe the TTartisan 23mm f1.4 is a brilliant lens and a bit of a step up in IQ over the 25mm.