Arch,
The CRF150's have had some cam troubles in the past -- all in all -- being an owner of one -- I'd stay away from Honda 4 strokes.
I have a CRF250, a CR250 and a TTR-125L. First off, to be blunt -- the TTR is fun as hell but the suspension is so limiting and the seat height is so low, my 5'9" girlfriend who probably has the same dirt experience as you do, out-grew it. No, she's not out-riding it, but she's so cramped that it's hard for her to stand and all that -- plus when you jump it even a little or hit a big whoop it bottoms out. You're also a lot heavier (thank god!) and as such, I think it'd be too small of a bike for you.
All that said, there *are* options for a TTR to make it more attractive because it is a bulletproof and unbelievably fun bike. I just put some YZ85 forks on my TTR (bolts right up with 2 spacers / washers) and ordered a new rear shock to stiffen up/raise the rear about an inch. Forks can be had for $250 on eBay and the shock was $220 brand new. The next thing I'll do is a big bore kit ($360) which moves it from the unbarable 8hp to about 12-14hp. This takes the stock seat height of 31" and moves it almost to CRF230 category, or about a half inch lower, not to mention the quality of the suspension improves greatly. The power to weight ratio is also better than the CRF230 and the end result is a bike that anyone can enjoy.
You may not "need" more power, but when you're going up even a reasonable incline, you have to wring it out (stock), otherwise it starts to bog down and then just flat out doesn't make it. You can make it if you just keep it open and go for it, but most beginners aren't able to do that and unfortunately the TTR doesn't have the grunt to get-going again.
All in all, if you want a bike for your SON, the TTR is great. If you want a bike for yourself, get a Kawasaki or Yamaha four stroke 250. Get the trail version if you want a little less maintenance, electric start and a less-high strung motor. It won't be too much bike for you, trust me.