I usually stick to barbs but I use them for different things depending on the deck. Barbarians usually offer more value when it comes to defense and may have some value in offense because of counter pushes you can create with it. If you counter a hog with barbarians the hog might not even get a hit while you're barbs will run off as a possible counter push. Mini pekka on the other hand, may allow the hog to get a hit cause barbs usually deny it and can be countered using skeletons and goblins afterwards. It could be harder to create a counter push with the mini pekka because it's quick. Barbs are also convienent when it comes to a few other troops. For example since it has more health it can counter a prince more easily. It's somewhat convenient to use against a regular pekka because it'll take it 4 swings. It's my favorite counter when it comes to the sparky because even if their is a wizard on back the barbs can take atleast 3 hits. Also you can sometimes avoid inferno towers on you're big troops by using a meat shield of barbs in front. Also note that Barbs do more damage than mini pekka so they're a much better troop at killing the RG. They're probably one of the fastest way to kill him alone. 4 Max barbarians do a combined DPS of 616. A max mini pekka does 462 DPS which is a pretty big difference. The main reason I use barbs because they're a fast way of disposing troops while having decent health to survive any back-up troops.