Was very happy with Tesco through the years I used them.
Never had a problem with fruit and vegetables, neither did other people locally – maybe we were lucky with our Tesco shoppers. Never had a problem with substitutions either, even before they changed their rules to ‘if we substitute a more expensive item, we charge you for the cheaper one you asked for’.
Only issue we did have was meat. Where we chose from a weight range, they nearly always sent a much heavier one, so it was a case of choosing a smaller one to pre-empt that, (it occasionally backfired).