Equity Research BB vs Corporate Finance Boutique

I work for a Big 4 firm in London within audit and valuations and I am coming up to qualification.

From speaking to recruiters it seems that my ACA is valued by tier 1 IBs and elite boutiques only within ER roles.

For a shot at BB or elite boutique IB I need some kind of M&A experience, which I don't currently have.

On the other hand they seem to like ACAs for ER so BB or a good boutique seems to be a realistic possibility, however my passion has always been for actual transactions and getting close to the action rather than simply trying to place a valuation on a stock.

I do seem to be having a lot more success when applying to regional boutique advisory firms.

My question is given the choice is BB ER preferable to boutique corporate finance in terms of:

Exit opportunities (long term I see myself on the buy side)
Compensation (I've been told ER is a shrinking market and salaries at the top vs banking reflect this)

Sidenote: I don't "time qualify" until September which is the earliest I would be able to leave for an ER role. If I go the CF route I can leave now as the experience goes towards the qualification.

What do you guys think?