From passing though, it's not pleasant, but not conspicuously worse than other London satellite-type towns.
You may or may not have heard about the notorious poem by future poet laureate John Betjeman called Slough that includes the line, 'Come, friendly bombs, and fall on Slough!'
Betjeman apparently wrote it more as a generalised objection to industrialisation than as a jibe against the place itself, but it stung the locals, and not long after its 1937 publication world events made the line seem a mite tactless.