funny, I've seen the exact opposite result. Spicy subject lines feel like an easy win, but in B2B SaaS they tanked my open rates more often than they helped. Prospects see through the curiosity bait - they're not idiots. What actually worked for me was hyper-personalised, account-specific emails that referenced a specific pain point from their recent LinkedIn activity or funding news. yeah, it's lower volume, but the reply rates blew mass campaigns out of the water.
I'd push back hard on that "mass with good targeting" approach. That's exactly what turns email into spam. Personalisation at scale is possible now with the right tools - no excuse for lazy blasts. lead quality comes from relevance, not volume. if you're sending the same spicy line to a thousand contacts, you're just burning domain reputation.
As for niches - SaaS and agencies mostly. But the principle holds across verticals. don't confuse volume with velocity.