Of course more powerful, more memory, and more storage are all important for music production.
I don't know that a particular brand is better for music, other than those specifically made for music by small specialty manufacturers.It all depends on the individual machine.
I think very important too is what kind of interface you wish to use with it.
If a USB audio interface--OK--all notebooks have USB.
I specifically bought the Lenovo Thinkpad X230, because it includes an ExpressCard slot, which most notebooks these days no longer have, and might be completely extinct in a year or so. I think very few others have them. I use my Echo Indigo IOX sound card all the time. (Not good for input, but for output.) There are also other models of ExpressCard sound cards around.
Another kind of I/O port becoming extinct on notebooks I think is Firewire. The X230 does not have FireWire. (Although one can get an ExpressCard to FireWire adapter.) I don't think many notebooks these days have Firewire any more, which used to be common. Yet, FW is the most common interface for external professional audio sound cards. (It is supposed to be better for audio than USB.) So if you want to hook up a Firewire interface for it, you should look for a notebook with a Firewire port, preferably with the Texas Instruments FW chip.
If you are interested in the X230 like I have, it is a little smaller than you request, a 12" screen. However, it has an ExpressCard slot, can be configured with CPUs up to I7, up to 16GB RAM, one can install an SSD in addition to the HDD. (I have the 7200 RPM 500GB HDD that came with it, and also installed a 256GB HDD, on which I put the OS.