In the past few days I've been benchmarking my own tool `choose` against BSD cut, GNU cut, and uutils cut and the uutils cut is certainly faster than BSD or GNU versions: https://github.com/theryangeary/choose/blob/master/benchmark...
The input file to the benchmark is all ASCII text chars (unibyte?) and `choose` does take the safe(r?) route and assume all text is UTF-8 and handle accordingly.
0:
| LC_ALL=C | LC_ALL=en_US.UTF-8 | not setting LC_ALL explicitly
-------------------------------------------------------------------
choose | 110.6 ms | 110.6 ms | 110.8 ms
cut | 813.9 ms | 983.9 ms | 971.7 ms
gcut | 172.8 ms | 172.5 ms | 174.0 ms
ucut | 78.22 ms | 79.39 ms | 79.38 ms