All comes down to nutrition prior to training. Training fasted or haven't had a meal in 2+ hours, I'd shoot for an intra containing carbs. If a pre-workout meal is in place, then IMO, no need for an intra (depending on type of training and duration). I will say, if in a gaining phase, there certainly isn't any negatives to supplementing with an intra shake whether a pre meal is in place or not.
I recently dropped my intra-carb shake and replaced with simple carbs post-workout. I do have my pre-workout meal roughly 90-120 minutes prior to training, so I am properly fueled. I haven't noticed any drop in performance at all.
I've actually just been drinking water for the first 40-60 minutes of my session, and then pounding an intra consisting of 1 scoop Amino IV, 1 scoop Ergonine, and 1 scoop High Volume (simply because around this time, its been almost 3 hours with no food, so I like to utilize the volumizers and amino acids at this time).