So i am thinking about downloading gdr3 preview for developers but is it worth it? Heard about a lot of bugs, and also if i do that will i still be able to get future updates like blue? Thanks in advance
If I'm not wrong, the update you'd get via Dev. Preview is the one HTC users got. So.. yeah, it's good I guess.
You will be be able to update to the official GRD3 (I think), as well as other updates, including WP 8.1.
Whether you update it now using the Developer Preview app or wait until your carrier releases it, you'll be getting the same update. It's up to you whether you want to have GDR3 now, or wait until it gets pushed and get GDR3 and Black at the same time (assuming your phone is a Lumia).