The main difference between corded and battery powered are Corded tools have all those pesky power cords to deal with and you always have to find someplace to plug the damned things in. However, they seldom run out of power when you need it most.
Cordless are very convenient, but have limited power and tend to go dead at the most inopportune moments.
Nowadays higher voltage in the battery powered tools isn't always the best choice. My most recent purchase was a small but very powerful 12 volt drill driver set with the latest generation of battery power technology. Provides plenty of power, lasts a lot longer between recharges and the batteries themselves are 1/2 to 1/3 the size of the older higher voltage battery packs.
I'd be wary of the multiple tool combo sets. They are usually not as high a quality tool as one would get when purchasing tools individually. I wouldn't buy a combo set unless someone I knew and trusted that uses tools regularly recommended a specific one to me.
YMMV.
