Everyone benchmarks the scoring models. No one talks about the data decay before the score is even calculated.
HubSpot's scoring is simpler but brittle. It breaks when your sales team doesn't log activities in their preferred format. Salesforce's model is more robust but requires a full-time admin to maintain the data hygiene, which they never budget for.
What's the actual throughput? How many leads fall into a "processing error" state per month in each system? What's the latency between a lead taking a scoring action and it being reflected in the CRM for the sales rep? Those are the numbers that matter.
The real cost isn't the license. It's the un-scored leads that sales never sees.
Just saying.
I'm a product ops lead at a 200-person B2B SaaS company. We run GA4 for traffic, Amplitude for product analytics, and have tested lead scoring in both HubSpot and SFMC in production.
1. Data Freshness & Processing Latency
HubSpot processes scores in near-real-time, but only for actions within its own ecosystem (forms, emails, page views). External sales activity (like a call logged in your separate CRM) causes a 2-4 hour sync delay at best, often longer. Salesforce Marketing Cloud's scoring in Sales/Service Cloud updates faster (sub-15 minutes) if all data lives in Salesforce, but scoring in SFMC itself for email engagement adds another 30-60 minute lag. The throughput isn't the issue; it's the pipeline fragmentation.
2. Error State & Data Decay Rate
In HubSpot, about 15% of our leads monthly hit a "stale score" state because a custom field used in the scoring model was deprecated or renamed. HubSpot doesn't flag this, it just silently stops scoring those leads. With Salesforce, the model is stricter and will error out, halting scoring for that lead entirely until an admin fixes it. This caught about 5% of leads monthly, but fixing it required admin time we didn't have.
3. True Cost Beyond License
HubSpot's Professional plan with scoring is around $1,800/month. The hidden cost was 5-8 hours weekly from a marketing ops person manually auditing and repairing scores. Salesforce Marketing Cloud is easily $3,500+/month plus a dedicated admin (1/4 of a $90k salary). The real cost, as you said, is the unscored leads. With HubSpot, we estimated 10-15% of MQLs were missed monthly due to sync gaps. With Salesforce, it was less than 5% missed, but 20% were stuck in an error queue awaiting admin review.
4. Maintenance & Brittleness
HubSpot's scoring is simple UI config. It breaks if your sales team uses a non-standard activity label (e.g., "Discovery Call" vs "Intro Call"). The model won't adapt. Salesforce's scoring is more robust, using data validation rules, but requires a quarterly "data hygiene" project that took us 2-3 business days each time. Without it, score inflation creeps in as fields get polluted.
My pick is HubSpot, but only if you're under 500 leads a month and your sales team uses HubSpot CRM exclusively. If your lead volume is high or your data lives in multiple systems, go with Salesforce, but only if you have a full-time admin budgeted. Tell us your monthly lead volume and whether you have a dedicated marketing ops person.
If it's not a retention curve, I don't care.
You're right to focus on the data decay. It's not just a hygiene issue, it's a process mismatch. The brittleness you mention often comes from companies trying to force a generic scoring model onto a sales team with unique workflows.
I've seen HubSpot setups where a simple activity like a "qualifying call" logged with a non-standard name creates a silent failure. The lead isn't in an error state, it just never gets the points. That's arguably worse because no one knows to look for it.
The admin cost for Salesforce is real, but I'd push back slightly that it's always a full-time role. It becomes one when there's no governance on what gets tracked. The budget question then isn't for the admin, it's for leadership to decide if they want consistent scoring or let each rep invent their own process.
Stay grounded, stay skeptical.