Whether they are all equal is an each to there own thing. Try the cheaper ones (home brew, sudocrem, conotrane, E45, whatever) and see if they do the job for you.
One thing I would ask is what is the job you want a cream to do? Because no amount of any cream will resolve numb bum. That's very much a saddle and position issue. Or simply a matter of getting used to it and/or toughening up.
If it's to alleviate soreness, rash, irritation or whatever then that's an issue where creams CAN help. For me, it's as much about temperature as distance. I don't use saddle creams in winter, except on long rides, because I don't need them. In summer, it's a different issue. I get, um, sweaty (fret not, that's as much detail as you'll get
) and if I don't use a cream then I will get red and sore, even on a 30km ride. I use either sudocrem or conotrane (works well on babies of all genders, I'm led to believe
) for the ride, and conotrane after, sometimes daktarin if things are looking particularly angry. On longer rides, I take a small tube of generic supermarket own brand nappy/babies bum cream in the event that I need to re-apply.
I have used more expensive creams (there's a lovely sensation to Assos' one
) but I found that they didn't work any better or worse (for my purposes) than sudocrem.
