Hi,
I have both Nikon and Cannon cameras and one is a is good as the other. Just getting used to my Cannon, they are slightly less user friendly but you soon get used to them.
Your camera has good low light capabilities for its price. For fireworks, I would be using manual mode and experimenting with different settings until you find the sweet spot.
For landscape if you can find a Sigma 10-20mm lens, these are superb for landscape photography and great value. I prefer it to much more expensive cannon and Nikon lenses I have. I work a lot in low light but mainly for concert and backstage photography. One thing I would get my hands on is Lightroom for editing, it is superb. Shoot in RAW if you have the software to work on raw files, end results will be much better. No doubt Snapper will be on here offering more in depth and great advice. I know he has some great snaps along the lines you are talking about.