Choosing between a boutique agency and a bigger name for B2B SaaS paid lead gen, how should I decide?

Been searching for a B2B paid media agency for about three months now. Were a mid-size SaaS company, around $8M ARR, selling to operations and logistics teams at mid-market companies. Our in-house marketing is two people, neither of whom have deep paid media experience, and weve been running Google and LinkedIn ourselves with pretty mediocre results. CPL is high, lead quality is inconsistent, and we have no real visibility into whats actually working because our conversion tracking has been a mess since we set it up.

Weve had calls with probably 12 agencies at this point. Most got cut fast, either too big and clearly going to hand us off to a junior team, too generalist with no real B2B SaaS experience, or too focused on SEO and content when what we actually need is paid lead gen.

Got it down to three and I've been sitting on this decision for two weeks now. Heres where I'm at.

Grounds for Promotion: Boulder-based, 14 years in which is basically ancient in agency years. Specialize in B2B paid lead gen on Google and LinkedIn which is exactly our use case. The person I talked to asked smart questions about our ICP and what a qualified lead actually looks like before pitching anything. Case studies show real numbers, CPL drops, lead volume increases, and they specifically mentioned getting into conversion tracking and call recording detail which is exactly what we need fixed. No long term contracts either. Only thing giving me pause is the team size, theyre boutique and I dont know how they handle capacity if someone leaves. Our CEO also keeps asking why theyre in Boulder like that even matters.

Directive Consulting: bigger, established in SaaS, clearly know the funnel without needing hand-holding. Strong methodology and a lot of content showing how they think. The hesitation is that wed probably be a mid-tier client for them and overpriced. Hard to know who'd actually be working on our account since reviews complain about turnover.

KlientBoost: High energy, strong on Google Ads, good track record on CRO alongside paid which is a bonus. They move fast and test aggressively which appeals to me. But they feel more DTC and ecomm leaning and im not sure how deep their B2B SaaS experiance actually goes. The sales process was very slick which sometimes means the delivery is less so.

So thats where im at. Budget is around $8-10k/month in ad spend with room to grow if results justify it. Primary goal is qualified demo requests, secondary is lowering CPL from where it is now.

Has anyone worked with any of these three recently? Or been in a similar position choosing between a boutique specialist and a bigger name? Would genuinely appreciate any input before I make this call.