And yet the Southern ones still look better IMO. Indeed many of the internal panels were removed on the Merseyrail units, but I'm not sure just how much better that was. Of course the internal coupler doors were replaced, but that's still quite limited work. Merseyrail units haven't had the windows touched either, which is a pretty major flaw.
Cost-wise Merseyrail spent some £33 million on refurbishing 59 units, Southern £6 million on 19. That cost Merseyrail about £560,000 per set and Southern about £316,000. I'd say given the relatively small difference in appearance between the two, that's quite a good saving from Southern.
I wouldn't say those on Merseyrail improved much in terms of cleanliness actually - faded seat moquettes that don't wear well. Having said that, they're a lot better inside than out: they're probably the worst kept trains in the country externally.
Pantographs are being removed at Stewarts Lane as part of the refurbishment programme. The first eight units to Lovers Walk (101/202/203/204/205/207/108/212) retained their pantographs; those to arrive after have lost them.