I'm biased towards my 600 monster however a I hear the 620's are a great bike too.
As for it being your first big bike - My son is 19, he rode a scooter for a year and gs 125 for a year, now he has a Monster 600 and loves it to bits.
He found no problem moving from a small to larger bike and he's built like a string bean!
I've never been tempted to change from my 600 for something more powerful on the road - but thats just me
