Howdy again time for another stupid noob question that I couldn't find an answer to yet.

Front fork material? I know alum is harsh and hear that steel, chromoly and carbon absorb vibration well but how do they compare to each other? How much different are they? The carbons are a lot more expensive and for the riding I am going to do.

Also, front and rear dereuliatlaiesialeirrer? Most of the ones I am looking at are altus or acera, a few have tourney front and altus rears, or altus/acera etc... Im coming from a beat up old junker so anything would probably be an improvement, is it worth trying to get any particular level of these? what does each step buy you?

(city, 10-20 mile leisure at most, hoping to get up to mid teens average mph) and right now I have a spreadsheet with 26 bikes on it trying to compare.

Thanks!