I ran the SunSpider JavaScript benchmark of the latest Opera 10.60 64 bit Linux build from here. Apparently, the JavaScript engine not only rivals but looks to be a little faster than Chrome, at least for 64 bit Linux. The tests ran in 411 ms on Opera and 477 ms in Chrome.

TEST                   COMPARISON            FROM                 TO             DETAILS

=============================================================================

** TOTAL **:           1.16x as fast     477.2ms +/- 4.9%   411.2ms +/- 3.1%     significant

=============================================================================

  3d:                  1.57x as fast      86.0ms +/- 21.5%    54.8ms +/- 8.7%     significant
    cube:              2.06x as fast      31.8ms +/- 12.8%    15.4ms +/- 15.7%     significant
    morph:             1.58x as fast      31.2ms +/- 24.0%    19.8ms +/- 6.9%     significant
    raytrace:          -                  23.0ms +/- 35.2%    19.6ms +/- 24.0% 

  access:              *1.11x as slow*    47.2ms +/- 7.1%    52.6ms +/- 2.1%     significant
    binary-trees:      *2.36x as slow*     2.8ms +/- 19.9%     6.6ms +/- 21.5%     significant
    fannkuch:          *1.28x as slow*    18.4ms +/- 12.3%    23.6ms +/- 6.0%     significant
    nbody:             1.41x as fast      20.0ms +/- 6.2%    14.2ms +/- 19.0%     significant
    nsieve:            ??                  6.0ms +/- 41.4%     8.2ms +/- 29.2%     not conclusive: might be *1.37x as slow*

  bitops:              1.75x as fast      37.4ms +/- 9.6%    21.4ms +/- 9.7%     significant
    3bit-bits-in-byte: 2.20x as fast       4.4ms +/- 37.9%     2.0ms +/- 0.0%     significant
    bits-in-byte:      1.68x as fast       9.4ms +/- 24.0%     5.6ms +/- 19.9%     significant
    bitwise-and:       5.92x as fast      14.2ms +/- 13.0%     2.4ms +/- 28.4%     significant
    nsieve-bits:       ??                  9.4ms +/- 22.1%    11.4ms +/- 9.8%     not conclusive: might be *1.21x as slow*

  controlflow:         ??                  4.8ms +/- 33.8%     6.0ms +/- 14.7%     not conclusive: might be *1.25x as slow*
    recursive:         ??                  4.8ms +/- 33.8%     6.0ms +/- 14.7%     not conclusive: might be *1.25x as slow*

  crypto:              *1.15x as slow*    26.2ms +/- 10.3%    30.0ms +/- 11.7%     significant
    aes:               *1.28x as slow*    13.8ms +/- 11.7%    17.6ms +/- 14.6%     significant
    md5:               ??                  6.8ms +/- 43.7%     7.4ms +/- 19.2%     not conclusive: might be *1.09x as slow*
    sha1:              -                   5.6ms +/- 25.3%     5.0ms +/- 0.0% 

  date:                1.55x as fast      80.8ms +/- 6.4%    52.2ms +/- 12.2%     significant
    format-tofte:      -                  29.2ms +/- 16.6%    25.6ms +/- 14.4% 
    format-xparb:      1.94x as fast      51.6ms +/- 17.2%    26.6ms +/- 15.4%     significant

  math:                1.55x as fast      63.0ms +/- 8.3%    40.6ms +/- 4.1%     significant
    cordic:            2.19x as fast      22.8ms +/- 18.7%    10.4ms +/- 21.7%     significant
    partial-sums:      1.35x as fast      28.0ms +/- 9.4%    20.8ms +/- 13.0%     significant
    spectral-norm:     1.30x as fast      12.2ms +/- 19.6%     9.4ms +/- 11.8%     significant

  regexp:              *1.32x as slow*    14.2ms +/- 11.4%    18.8ms +/- 11.8%     significant
    dna:               *1.32x as slow*    14.2ms +/- 11.4%    18.8ms +/- 11.8%     significant

  string:              *1.15x as slow*   117.6ms +/- 4.6%   134.8ms +/- 2.0%     significant
    base64:            ??                 14.8ms +/- 16.2%    16.6ms +/- 10.0%     not conclusive: might be *1.12x as slow*
    fasta:             *1.15x as slow*    20.8ms +/- 9.8%    24.0ms +/- 8.2%     significant
    tagcloud:          *1.40x as slow*    27.6ms +/- 5.1%    38.6ms +/- 5.4%     significant
    unpack-code:       1.19x as fast      33.6ms +/- 5.0%    28.2ms +/- 3.7%     significant
    validate-input:    *1.32x as slow*    20.8ms +/- 10.7%    27.4ms +/- 4.1%     significant