Not the OP but, when I did consulting/advisory work, we mostly did a combination of value-based and nominally value-based.

What I mean by that is our large clients had subscriptions with us for advisory services, which included or could include some specific deliverables like reports but was mostly fairly open ended access for inquiries, press references, etc. I put these mostly in the value-based category.

Then we had things like advisory days, speeches, etc. we priced on the basis of the deliverable value--but in practice there was a fairly close correspondence to time spent. In practice also, clients would end up turning a one day session into two half-day sessions for different groups, so from their perspective they were mostly buying our time on-site (plus travel, etc.). We tried to hold the line on pricing for value but I'd say we only had some success here.

We'd also do custom research etc. for clients which, from their perspective, was almost certainly more value-based as much of our work was out of their sight. (Of course, from our end, we were mostly coming up with that pricing from a desired internal day rate.)

I think the only time we nakedly charged by the hour was when we were doing legal work because that was just the way the law firm which was our direct client worked. (TBH, it was pretty nice to get a healthy hourly rate for everything and it was a substantial job. Also somewhat open-ended work we weren't particularly familiar with, so an up-front quote would have been difficult.)

My biggest challenge with value based pricing (VBP) was that it required an upfront discussion about the perceived value of the work, and my prospects/clients were often totally in the dark about "value".

I don't think VBP works well for tech/biotech startups:

-founders/exec can't define value

-founders/execs are selling the dream (= infinite value) and don't want to pay for it.

-startups want to hire brains, but pay for hands

-founders/execs and especially managers want to focus on (minimizing) "costs", rather than unearthing or creating "value" with consultants.

[Edit: formatting]

Yes, we worked for (or at least were paid primarily by) mostly old-line enterprise IT companies. We talked to plenty of startups. But they mostly couldn't/wouldn't afford us even when we had good personal relationships with the execs. ADDED: I do know at least one firm that does mostly value-based advisory work for small companies; their approach is to have a fair number of low dollar small clients in addition to some larger ones.

As I said, even with the big cos, a good chunk of what we did was at least roughly day-based. At one point, for example, we experimented with trying to price more strategic advisory work higher than make-your-product-launch-deck-better type of work and it never really flew.