I would stay away from a Gemeinhardt 3SB as an upgrade from a Yamaha 200 series flute. In fact, if you had a Gemmie 3SB and wanted an inexpensive upgrade, I would suggest a Yamaha 221 with an upgrade headjoint, such as the Yamaha EC.
The Yamaha 361 and 461 will not be very different from your 221 flute, because the headjoint is engineered and cut exactly the same way. The Yamaha CY headjoint is a good one, and it suffices for most players through high school. The differences will be:
1)Open holes. If you are studying jazz flute seriously, and you have a genuine need to do microtone trills, glissandos, and play above high C into the 4th octave, you will need open holes. The fact is, though, that MOST players have no need for them and simply plug them for a more comfortable, ergonomic hand position.
2)A B-footjoint. Once again, the actual need for a B-footjoint is not very common. In fact, some pro players are fitting their B-foot flutes with a C-footjoint to keep a lighter weight, leaving their B-foot at home for when they need it. They generally DON'T need it, and the B-foot sits in the closet and rots.
3)More sterling silver. The Yamaha 361 has a silver headjoint, and the 461 has solid silver tubing throughout. Both have silverplated mechanism and keys. The silver weighs more, but you will pay a LOT more money for the 'sterling brag factor' than the sterling silver is actually worth. Once again, the engineering/tonehole placement/headjoint cut are the same as the Yamaha 221 flute.
Step-up flutes are almost ALWAYS simply beginner flutes (same headjoint, tonehole placement, engineering, etc) with more sterling, open holes and a B-foot.
Do you really want to pay for an upgrade and get a beginner flute, in sterling silver?
The headjoint has a huge effect on the playability and response of the flute. You can buy a new pro headjoint for $750 to $1200, and find a good used one for $400 or less.
If you try out a new Yamaha and it plays much better than your own flute, it is highly likely that your own flute needs adjusting for leaks. I would take your 221 in for a clean, oil and adjust- to a very good flute tech- before even trying a new flute out.
New flutes also almost always require a tech to go over them and make adjustments. Whatever new flute that you try out and like will most likely have had the best set-up job.
You will get the most upgrade for your money by doing 2 things:
1)Have your flute serviced by a top flute technician
and
2)Find an upgrade headjoint for your current flute.
I would start by trying a Yamaha EC headjoint. You could also try, for example, a Prima Sankyo NRS-1. There are often used pro headjoints on eBay, and
http://www.usedflutes.com
And the previous advice to try flutes out and see which one suits you best is excellent advice.
