Carbide inserts can produce better surface finishes, because the tool will maintain its edge for a longer period. Part of getting a good finish is related to a high surface footage cutting rate. HSS just cannot go fast enough in machining steel without burning up before it gets above the critical speed where the surface finish improves.
In aluminum, you can generally use all the rpms that your spindle can muster. Aluminum is easily scuffed, and the sharp corners of a conventional endmill tend to be bad for this. I like Iscar helimills (and facemills). The special inserts for aluminum can produce a remarkably smooth surface with the end of the mill.
If your plan is just to buy a face mill for facing surfaces without shoulders, the tool you referred to is probably going to work better than what you are using now. You might want to check on the insert availability for that tool. Look for "wiper inserts" to get the best facing finish, at a healthy feedrate, providing that your machine is accurately trammed.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)