IMHO, Central's two best units are 170397 and 170398, the 3 car Porterbrook "spot hire" units. These have Central style interiors, but the middle car has an MML style First Class section, although not the buffet area. My favourite bit when I have that pair (sadly very rarely, IIRC I've had then twice in all my CT journeys) though, is the section behind the drivers cabs. These have seating similar to that in that area on the MML 170s, although in standard CT style, but they are arranged in 2+1 layout, making the area very spacious, especially when using the single row on the right hand side (which I do), and also have sockets and table lights. They are also in much better condition than the ex-MML 170s, being almost 4 years newer, and AFAIK not heavily used early in their lives. Sadly they are showing neglect though, and the last one I went had the table lights not working (most had the switches broken) and worse, as seems common with the smaller type of First Class seat on the 170s (as in the end sections on the MML 170s), a number were failing to lock in the normal position, forcing passengers to sit reclined. The latter must show something about modern seat design quality, since I've rarely known the reclining mechanism on the IC70s (the seats in Mk3s and Mk2fs) to not work perfectly, even on sets which have shown numerous signs of neglect and various other faults. On the other hand, the 170s seats, and many other modern types seem difficult enough to work at the best of times, usually requiring a lot of force, and often don't work at all. Even the design of the locking control was easier to use on the IC70s than many modern types.