There are many dependable powerful sized engines in this class.
In testing done by CLARENCE LEE there is 5 very powerful!,

("THESE ARE NOT IN ORDER OF MORE TO LESS POWERFUL")

1. TOWER HOBBIES 46 (HAVEN'T TRIED ONE)
2. K&B 48 "SCREAMING 48" (MY FAVORITE)
3. THUNDER TIGER PRO 46 (ANOTHER ONE OF MY FAVORITES)
4. GMS 2000 46 (HAVEN'T TRIED ONE)
5. OS 46 FX (TRIED MANY)

Also remember you can go to a 70 sized 4 stroke in an 40 size aerobatic ship and you'll like it also.
(i fly a OS 70 4 stroke in a GLOBAL AVENGER)
( A MAGNUM 91 4 STROKE IN A GLOBAL ULTIMATE BIPE)

The 4 STROKERS GIVE YOU THE TORQUE TO PULL LARGER PROPS and in turn you generally can pull through the vertical manuevers with out needing "built up" airspeed.


REMEMBER one thing though, the more powerful you go, the more advanced the timing and internal complexity of the engine is.
They can be very touchy on the needle valve settings. when you get a carb,timing and porting combination that is easy to tune, you're going to loose power. when they get more involved in the above settings(timing,porting etc.) then the more precise you have to be in the tuning, setting up. and more powerful the engine "usually"is.
I have bought three K&B 48s from guys I fly with who say they can't get them to run! (my gain their loss) The SCREAMING 48 just takes a little more tinkering to get everything set for quick response,idle and top end. but what an engine when it's set up right.
The THUNDER TIGER PRO 46 is very dependle,powerful and easier to tune.. I have one with a tuned pipe ( in a HOBBICO SPECTRUM)and one with the stock exhaust.(in a H-9 advance) both are easy to adjust and you don't have to mess with them once they are set up. (THIS WOULD BE MY ENGINE RECOMENDATION FOR YOU!)
I will give OS credit where credit is due, but you're paying for the name! they are more expensive then any but the K&B 48. (last i checked they were the same price, but the K&B will run circles around the OS 46)

In reading what you said the problem your engine gave you IN THE AIR, I'm going to guess that YOU HAD IT SET TOO LEAN!!!!

When you set your needle valve on the ground remember the engine is going to "UN-LOAD" in the air. (forward air speed is going to make the prop turn faster) and that will can you a LEAN run in the air.and by what you described yours was doing that's what it sounds like. When you set your high speed needle on the ground, do "THE PINCH TEST" I do mine with a "TACH" I want 200 RPM increase AT FULL THROTTLE when I pinch the fuel line to kill the engine.(on a well broke in engine) I do this for the TOP END and BOTTOM END (idle) many hold the nose of the aircraft in the air AT FULL THROTTLE to make sure the rpm doesn't drop, there is nothing wrong with this and if you don't have a "tach", do it.
But if you have a tach or can get one use it as I have described, I think you'll be pleased.. I'll add one more thing, BREAK THE ENGINE IN THE "EXACT" WAY THE DIRECTIONS TELL YOU TO! And on a test stand NOT in "THE AIR".

JUST MY LONG WINDED OPINION!

// OH YEA, there isn't a thing wrong with the MAGNUM 46 BB engine (I have two of them in trainers) they're just not as POWERFUL. and that's what you asked for!

RON in NEVADA