I've been following his career since he started in cadets karting throughout the past years. Last year he had an incredible winning streak in karting setting some new benchmarks with several major titles both European and World Championships. I've already been waiting until this subject would pop up here.
This kid is a natural talent, when he started openwheelers he did a season in the Florida winter series in February/March coming straight from karting he gave the Ferrari academy talents like Fuoco, Latifi a real go on track. Verstappen also performed different test with F2.0 teams and it all headed into the direction that he would step in that class for this year until he did a F3 test with Motopark at Valencia setting a new lap record with I think a German F3 car finding out that the F3 car suited him much better. After that it was decided to step into the completive field of Euro F3 which is a very close field. After his recent streak of 6 wins it all went very fast, it didn't stayed unnoticed especially for a kid who is racing open wheelers for about 8 months now.
As for the move, I am not sure personally I thought even F3 was to high for him and he would only fight for 4th to 10th spot. But he has been driven like he has been in that car for a full season, making a very quick and easy adaption to these cars.
The question now is, is F1 really a step to far ? It has been done in the past, it didn't happened much but remember Kimi I think he had only one year in F2.0 or something, before he got into F1. Even his own dad Jos Verstappen, yes he got also very quickly in F1. years of karting, one very successful year of German F3 and then into F1 with Benetton (although for him it went to quickly) But Kimi got WCD at some point.
Bottom line is now and then you have a exception of the rule, maybe Max is one. I advise everyone to watch back the 2nd F3 race at the Norisring. He showed a bit of (well maybe I should not mention but I do) Senna likish driving in the wet raping everyone with almost 1 second faster in lap time in the wet. Its those kind of races when you see the talent excel from the exceptional drivers, and obviously this didn't stayed unnoticed to the team owners.
Personally I don't think they will jump straight into F1, it seems like his preference is with Mercedes but the question is what can they offer Max. Also Helmut Marko seems to be a huge fan of Max and offered him a seat in Toro. But if I have to say it, I think it will be more like this.
I think he could be a 3th driver for RBR/Toro Rosso, perhaps do some test days during winter and then drive in GP2 or F3.5 (with backing from a F1 team) for 2015 to jump into F1 for 2016. That's my feeling but then again, when you get such a chance anyone would take it. So Im not surprised if he will be on the F1 grid next year.
One thing is for sure with this kid, when you have followed him, see his results and how easy he adapts and progress. Its not a matter of if,...... but more the question of when he will be in F1.