I have a few hundred feet of Plus-X 125 left. When that's done, I'll need to find a new 100/125 speed film. Thing is, I'm cheap and lazy, so I like developing in D-76 at 1:1. And Plus-X is fast (7 minutes at 1:1, 4.5 minutes at stock).

When I look at my options, they take a lot longer to develop.

Across 100, 10.5 minutes
Delta 100, 11 minutes
Fomapan 100, 10 minutes
FP4 125, 9.5 minutes
Kentmere 100, 11.5 minutes
Rollei RPX100, 8 minutes
Tmax 100, 9.5 miuntes

Only the Rollei is in the same league as the Plus-X - and it is not cheap (almost twice the cost of HP5+)
Okay, I'm not going to moan too much about adding 4 minutes to a process that, all told, takes me almost an hour (from loading the reels to hanging the negatives).

But it raises the question, why do all the still-produced films take longer to develop than Plus-X? Was Plus-X simply a higher silver content? (I recall someone saying the reason Kentmere takes so long to develop was due to the lower silver content)