Let me tell you the difference from my opinion. Not much. I have 3 gens ace 5000, 40c. 1 Excellion 6000, 60c, 1 Team Orion 6500 90c.

Here is the difference. I run in the Losi SCTE in my sig by the way. In a 5 minute heat you will not notice a difference. I suggest get 4 gens ace for the price of 1 of the others. I notice that the gens ace starts to lose a little of its punch right around the 7 minute mark. If your club runs 7 min. mains like a lot of groups are doing you should be fine. From the 7 to 10 min. mark I do notice a bit more punch and overall power with the Orion and the Excellion. Plus, I could not quite make a 10 min main with the Gens Ace, no problem with the Orion and Excellion. All in your budget, but I would start with Gens Ace and work your way up in the future!

It might be the charger I use, but I usually put 5400 in the Gens Ace if I run them down to LVC so they may be under rated.