Never heard of MZ forks but googling them threw up a similar question to yours, same frame, from 2009 >
http://www.bikeradar.com/forums/viewtop ... p=15301448It appears (and by the looks of your photo) they are cheap basic forks, dont know aht the dials on yours do, but they look like the elastomer/spring type and the dials on top just compress/uncompress the elastomer/spring a bit.
As for better/decent forks, take your pick, they range from £100+ to £1000, most of us on here started life decided to buy bits on a budget before full blown mania sets in and you end up spending a few grand
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The most common 'decent'; brands are Fox, Rock Shox and Marzocchi, plenty available second hand on Ebay and Pinkbike but bear in mind a knackered fork may need servicing or you can go the DIY route, some forks are easier than others to DIY service.
Your frame will have a suggested fork length or travel so you will be constrained by that (unless you want to knacker the geometery and strength of the frame), so find out the travel of your forks..maybe 120-130mm or so and look for similar, they wont be long travel so you can discount DH/triple clamp forks....good Fox's even 2nd hand tend to be a bit more pricey, Marzocchi (esp older Italian ones are popular, strong, reliable, etc)..Ive just put Rock Shox Domains on my new build, got new ones for £175....and Im pleased with them.
Is your rear shock working ok, Fox are pretty reliable, the basic models with only rebound adjuster (im sure yours would have that ?), are find, you dont need tons of adjustment on rear as it can complicate things.
Andy