Take it from the other side of the counter, your 10 year old (and you), will be much happier starting off with an electric.
The AE RC18 series of rtr's is IMO the hands down best beginner car available, especially for someone as young as 10. You can get one in off road monster truck, stadium truck, or buggy, and if he wants on road, several different body styles are available to choose from for the 18R. For around $150 you get everything (including a battery) needed to play with the car and he can be driving it full tilt in about an hour after opening the box, indoors or out. Instant fun, no waiting, and no real r/c specific expertise required. If you read the instructions and can connect a couple of plugs, you can make it work. Aftermarket and upgrade support for the RC18 is very deep, and it's a rare hobby shop that does not carry the AE brand. There are plenty of other cars/trucks in the same class as the RC18, but none are as durable and only a handful are as well supported.
One of the major downsides to nitro for a 10 year old is it REQUIRES you to supervise and/or help him in order to run the car. If you are looking for something that gets you more involved with your son, nitro is one way to do it, but keep in mind that without nitro specific expertise, most of that time will be spent in mutual frustration as you try to get and keep a nitro engine running until you either gain the required knowledge or give up on it. The nature of nitro engines is brutally unforgiving, a quarter turn of the wrong screw can cost you up to $200 (or more) to replace a burned up nitro engine before you ever get to drive it.
If you do decide to go nitro, please, please, please, do yourself a big favor and deal with a local shop with a good rep for customer service as you will be needing plenty. That's not to say you can't buy a car off the net and get local help from a shop, it's just that a good local shop will usually give you (free) service/help after the sale where you would otherwise have to pay for the same help if you don't buy from them. The few bucks you save buying a car on line will quickly be eaten up if you have to pay for help just to get it going.
If you do go nitro, take a hard look at the Traxxas nitro sport. It's inexpensive, tank tough, and as durable (or more so), than a lot of cars costing twice to three times as much. More importantly, Traxxas nitro vehicles come with the most complete and comprehensive set of nitro beginner friendly instructions in the business. As a beginner, you will stand a better chance of enjoyment from nitro with a Traxxas product than you will with any other brand and like AE, it's a rare hobby shop that does not support the Traxxas brand.