A Smith puts the ROM too much in a fixed position. You have to, more or less, move the weight in a straight line. The body does not function like that. BB row's (or most any other exercise) follows more of a natural strength curve. Usually divided into 3 phases (lots of sport clinics show that very well with graphs, video's, etc....can look it up on the web also). The squat and BP are good examples.
Only my view but using the Smith with anywhere near max weight & full reps may be a mistake for some. Could very well encourage injury. Though if anyone is doing short range (1/4, 1/3 reps, which many of the really huge BB'ers do) than the Smith may serve a purpose in that way. Only you can be the judge of results through experience.
Quite a few trainee's have success on a Smith. Though mainly for moderate weighted BB'ing exercises. As far as concentration goes, either Smith of a BB can accomplish that. Though a BB may offer less chance of a major injury. Each can gorge the upper back with a full muscle pump beyond what thought was possible, if that is the goal. But again, a Smith is not designed for heavy strength training. If wanting another way for a good pump, than SS pullovers (straight or bent arm) before Smith or BB rows. More of a pure BB'ing style of working out.
If wanting more focus on the lats/back than lay face down on a bench, using either a Smith bar or regular BB, and do rows that way. DB's work very well here also. If your gym (Tbombz's probably does) has a Nautilus pullover type of machine (3 phase...with short lat bar attached) than you have an excellent lat/back builder. You hit the mother load. Good Luck.