B2B Insights
August 6, 2025
Content Writer for Whistle with multidisciplinary experience spanning over a decade.
Hiring a trusted SDR offshoring agency can transform your outbound sales program, cutting costs, speeding up ramp time, and unlocking new markets without the headache of hiring in-house.
The challenge? The outsourcing scene is crowded. Every agency promises quality leads and cost efficiency, but not all deliver. The best way to separate signal from noise is to start your search on reputable review platforms, where verified client feedback, case studies, and transparent ratings help you make informed decisions.
Below, we highlight five platforms where you can find vetted SDR partners, compare capabilities, and choose an agency that aligns with your goals.
Why it’s worth exploring:
Clutch.co is one of the most recognized B2B review platforms, featuring in-depth case studies and ratings for thousands of agencies worldwide. Their detailed filters allow you to search by service focus (like sales development), location, budget, and company size.
What sets Clutch apart from other platforms is their rigorous verification process. Every review goes through analyst validation, meaning you’re reading genuine feedback from real clients who’ve actually worked with these agencies. This eliminates the noise of fake reviews that plague other platforms.
Key benefits:
The platform’s strength lies in its comprehensive agency profiles. You’ll find detailed information about team size, hourly rates, notable clients, and specific service offerings. Most importantly, Clutch provides context around each review: you can see the project scope, budget, and timeline that led to specific feedback.
Pro tip: Look for agencies with multiple recent reviews and a consistent rating above 4.5 stars—this shows both performance and stability. Pay special attention to reviews from companies similar to yours in size and industry.
Why it’s worth exploring:
G2 is primarily known for software reviews but also features service providers, including SDR offshoring companies. Its real strength is the volume of authentic user feedback; millions of professionals contribute reviews across industries.
What makes G2 particularly valuable for SDR agency selection is its focus on user experience and satisfaction metrics. The platform breaks down reviews by specific criteria like ease of collaboration, quality of deliverables, and return on investment, giving you granular insights into what working with each agency feels like.
Key benefits:
G2’s Grid methodology is especially useful for understanding market positioning. Agencies are plotted based on customer satisfaction scores and market presence, helping you identify both established leaders and emerging challengers that might offer better value or specialized expertise.
Pro tip: Use G2 to validate an agency’s tool stack expertise (e.g., HubSpot, Salesforce, Outreach.io) if you need tech alignment. The platform’s integration reviews can save you from compatibility headaches down the road.
Why it’s worth exploring:
GoodFirms is another trusted directory that lists B2B lead generation and SDR agencies globally. It offers curated lists based on research methodology, client feedback, and market penetration.
GoodFirms distinguishes itself through its research-driven approach to agency evaluation. Their team conducts independent research to verify agency capabilities, going beyond client testimonials to assess technical competencies, team expertise, and market reputation.
Key benefits:
The platform excels at showcasing agencies that specialize in specific niches or serve particular market segments. If you’re a mid-market company looking for personalized attention rather than enterprise-scale operations, GoodFirms often surfaces hidden gems that larger platforms might overlook.
Pro tip: Combine GoodFirms research with LinkedIn references to check cultural and communication fit. The platform provides team member information that you can cross-reference for additional validation.
Why it’s worth exploring:
UpCity focuses on building trusted relationships between businesses and service providers. While smaller than Clutch, it has a growing directory of outsourced SDR and lead generation partners with transparent reviews.
UpCity’s unique value proposition is its emphasis on partnership over transaction. The platform prioritizes agencies that demonstrate long-term client relationships and collaborative approaches, making it ideal for companies seeking strategic partnerships rather than one-off projects.
Key benefits:
The certification system helps identify agencies that have demonstrated consistent performance and client satisfaction over time. These badges aren’t just marketing fluff—they’re based on verified client outcomes and retention rates.
Why it’s worth exploring:
DesignRush is best known for creative agencies but increasingly lists sales and lead generation companies. Their editorial “Best Of” lists are helpful for quickly spotting vetted SDR agencies.
While DesignRush might seem like an unexpected choice for SDR agency selection, its editorial approach provides valuable context that purely review-based platforms miss. Their industry experts analyze market trends, agency capabilities, and client success patterns to create curated recommendations.
Key benefits:
The platform’s strength lies in its ability to surface agencies that excel in specific verticals or service areas. Their editorial team identifies emerging trends and highlights agencies that are adapting to new market demands.
Finding a list of agencies is just step one. To choose the right partner, you need to dig deeper into their capabilities and cultural fit. Here’s how to evaluate your shortlisted candidates:
Looking for a partner you can trust, without endless vendor research? Whistle has delivered millions in pipeline for B2B brands through outsourced SDR services.
Talk to us about building your sales team.
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