Sorry for popping this in this thread but it was the first one I came across that seemed remotely relevent...
158888 was on hire to Northern today... and I have to say, the standard of the unit compared to the Northern examples (even the so-called refreshed/refurbished ones) was beyond comparison!
The engines sounded smooth, the interior was how a modern unit should look. Now, if only that standard of refurb was applied to all units...
Conversely, was on one of the 180's on the way home; my GOD! How scruffy was that unit. Looked like a mechanics skip.