Fair enough, I didn't realise that people were that tight/savvy that they'd sit on a Pacer for best part of two hours instead of a 185s for best part of an hour - I can't argue with your "first hand" experience though.
The Caldervale line is certainly the prettier of the two
For a start at least 2/3rds of Calder Vale services are 155s or 158s. Even when you get a 142 or 144 it sometimes has a 153 tagged on to it. There's also quite a few Manchester-Hulls that are 170 operated. I actually prefer 170s to 185s so I wouldn't say it's an inferior unit. However, the TPE 170s are only 2 car so there is a higher risk of having to stand.
I've just had a look in to pricing and journey times on Caldervale vs North TPE.
For one person:
Leeds-Manchester Route: Any Permitted Anytime Return: £24.20.
Leeds-Manchester Route: Hebden Bridge Anytime Return: £18.40.
Leeds-Manchester Route: Any Permitted Off Peak Day Return: £16.50.
Leeds-Manchester Route: Hebden Bridge Off Peak Day Return: £14.80.
For two people:
Leeds-Manchester Route: Any Permitted Off Peak Day Return x 2: £33.00.
Leeds-Manchester Route: Hebden Bridge Duo Ticket: £22.20.
Journey times:
North TPE: around 55 minutes
Caldervale: More variable. Fastest 1hr35.
So imagine if you're a couple living in Leeds who go to Manchester together around 24 times a year on leisure trips and aren't ever in a rush to get there or back:
On North TPE that'd cost £792.00
On Caldervale that'd cost £532.80
Over a year that'd save you over £250 using Caldervale.
I do, however, appreciate the extended journey time wouldn't be of interest for someone living in Leeds and working in Manchester or vice versa unless they are very short of cash.