Don't read Abnett, thank me later. First and Only and Necropolis excepted for 40k, and Riders of the Dead for fantasy excepted. His stuff gets very cliched and samey.
Generally, the books were better when they were written by known authors, not people that wrote the rules giving being a novelist a go. The franchise got to the part where they realised they could stick their logo onto anything and it'll sell.
The stuff by Jack Yeovil (better known as Kim Newman) were brilliant, most of Bill King's stuff was very good, likewise Brian Craig (better known as Brian Stableford)