We recently got a new Nokia N93 at work and had the fun task of benchmarking it.
In raw processing power when running Java it outperforms the second best phone we have (the Nokia E61) by about 50%. Unfortunately, like all the Nokia handsets, it’s not so good at image handling and so unfortunately loses out to Sony Ericssons overall.
The big disappointment though is the hardware acceleration. 3D graphics in J2ME should theoretically be done using JSR 184 (an API for 3D graphics - there is at least one other but JSR 184 is the most supported). The N93 has hardware acceleration supporting OpenGL ES and according to the documentation the JSR 184 implementation automatically uses hardware accelerated OpenGL ES if it is supported.
Unfortunately the performance suggests otherwise - the N93 handles one of our 3D games almost as well as an N73. My guess is to get the proper hardware acceleration you need to write Symbian apps…