Hiya, I've been using the above software for four years - I started with Magix a German company but couldn't get on with it !!!!, and cannot recomend it !
With Cakewalk I tried using the line - out of a Marshall valvestate, bit I had a lot of Hum problems when using the distortion channel.
Now i use a Digitech Artist modelling guitar proccesor through a Volume control I made ( which is a 470Kohm Potentiometer) straight into the Mic input, it gives a very Hum free sound - for the vocals i use the clean channel of the valvestate.
Cakewalk Guitar Tracks is simplicity to use, I think there is a proffessional version available now and I might well upgrade.