I seem to recall that Heng Long are dropping the IR option on their tanks, so it will be BB's only. They have a whole range of tanks, and they are all good runners, with cheap replacement parts, and a million upgrades available if you take that route.
Nicest runners that I have owned from the range are the Bulldog, Panzer III, and Sherman, but none of them are going to cause problems.
For a 5 year old I would choose something with a short barrel, as they will be less likely to ram it into immoveable objects.

I would also budget for quailty batteries and a charger, as the HL ones only last a short while before they need a recharge.