There is a review of both the Ninja 500 and the GS500 on this website.
If you simply must go with a bike bigger than 250cc, they are great bikes. They are not merely beginner bikes, both have long histories as very good inexpensive sport touring rides.
That said, wait until you’ve done your MSF before making a commitment to buy one. Things happen much faster on a 500R than on a 250R – especially when things start to go wrong. If you handle the MSF without concern, go for a 500. If you has reservations, give the 250 some more consideration.
Having started on a 500 myself, I’ll say one word of warning – that much power eggs you on. It is much easier to get in over your head (over confidence) on a 500 than a 250.
Its all about knowing yourself.
Ride safe.
.
