This comparison of OO extensions of Tcl is based on
OO benchmarks of the OO shootout
[http://www.bagley.org/~doug/shootout/]
and consists of the 
[OO Method calls]
(source [http://www.bagley.org/~doug/shootout/bench/methcall/])
and the [Object Instantiation Test]
(Source [http://www.bagley.org/~doug/shootout/bench/objinst/]).

These tests were performed with XOTcl 1.2.0 on a Pentium 4 M 
Notebook with 1400 MHz under Fedora Core 1.0.

 XOTcl
   methcall:  0.470u 0.000s 0:00.41 114.6%       0+0k 0+0io 347pf+0w
   objinst:   0.960u 0.000s 0:00.97 98.9%        0+0k 0+0io 348pf+0w
 ITcl emulation in XOTcl
   methcall:  0.590u 0.000s 0:00.62 95.1%        0+0k 0+0io 351pf+0w
   objinst:   1.780u 0.000s 0:01.81 98.3%        0+0k 0+0io 353pf+0w
 OTcl
   methcall:  0.980u 0.000s 0:00.95 103.1%       0+0k 0+0io 329pf+0w
   objinst:   2.370u 0.010s 0:02.37 100.4%       0+0k 0+0io 329pf+0w
 itcl
   methcall:  0.870u 0.020s 0:00.92 96.7%        0+0k 0+0io 347pf+0w
   objinst:   1.790u 0.010s 0:01.84 97.8%        0+0k 0+0io 348pf+0w
 stooop
   methcall:  1.690u 0.010s 0:01.73 98.2%        0+0k 0+0io 326pf+0w
   objinst:   4.020u 0.010s 0:04.06 99.2%        0+0k 0+0io 316pf+0w
 classytcl
   methcall  0.740u 0.010s 0:00.78 96.1%        0+0k 0+0io 335pf+0w
   objinst   3.020u 0.030s 0:03.09 98.7%        0+0k 0+0io 335pf+0w

The full source and results are available at 
[http://media.wu-wien.ac.at/download.html].