I deploy both Microsoft Teams Phone and standalone VoIP systems. I have no loyalty to either. Here is my honest assessment of when each one makes sense — and when it absolutely does not.
When Teams Phone Wins
| Scenario | Why Teams Phone |
|---|---|
| Already paying for Microsoft 365 E5 | Phone is included — adding another system is redundant |
| Entire company lives in Teams | One app for chat, video, and calls reduces context switching |
| IT team is Microsoft-certified | They already know the admin center |
| Simple calling needs (< 50 users) | Basic inbound/outbound with auto-attendant |
When Standalone VoIP Wins
| Scenario | Why Standalone VoIP |
|---|---|
| Call center / high call volume | Teams Phone lacks real ACD, queue management, and analytics |
| CRM integration is critical | Teams CRM integration is limited to Dynamics (most use Salesforce/HubSpot) |
| Call quality is the top priority | Standalone VoIP providers optimize for voice; Teams optimizes for everything |
| You need call recording with compliance | Teams recording is basic; standalone offers granular controls |
| Multi-vendor strategy | Depending on Microsoft for comms + productivity + email = single point of failure |
| Budget-sensitive (< M365 E5) | Teams Phone add-on + Calling Plan = $20-32/user vs $20-28/user standalone |
The Real Cost Comparison
This is where most analyses get it wrong. They compare Teams Phone license ($8/user) to standalone VoIP ($24/user) and declare Teams cheaper. But that is not the full picture.
| Cost Component | Teams Phone | Standalone VoIP |
|---|---|---|
| License | $8/user/month | $0 (included) |
| Calling Plan (domestic) | $12/user/month | $0 (included) |
| Microsoft 365 (required) | $12-57/user/month | Not required |
| Total if you HAVE M365 | $20/user/month | $24/user/month |
| Total if you DON'T have M365 | $32-77/user/month | $24/user/month |
If you already pay for Microsoft 365 Business Premium or E3/E5, Teams Phone is competitive. If you do not, buying M365 just for phone is wildly expensive.
Call Quality: The Uncomfortable Truth
| Metric | Teams Phone | Standalone VoIP |
|---|---|---|
| Average MOS (my measurements) | 3.9 | 4.2-4.4 |
| Consistency | Variable (depends on Teams client load) | Consistent |
| Codec | Silk (proprietary) | Opus/G.722 (open standard) |
| Jitter handling | Good but not best-in-class | Purpose-built jitter buffers |
Teams Phone quality is acceptable for most users. But if you are a law firm recording calls, a sales team making 100 calls/day, or a support center where every call matters — the 0.3-0.5 MOS difference is noticeable.
The reason: Teams is a collaboration platform that also does phone. Standalone VoIP is a phone platform. When you optimize for everything, you are best-in-class at nothing.
My Recommendation
Choose Teams Phone if:
- You already have M365 E5
- Your calling needs are simple
- You want fewer vendors to manage
- Call center features are not needed
Choose standalone VoIP if:
- Call quality is mission-critical
- You need real call center features (ACD, skills routing, wallboards)
- You use Salesforce, HubSpot, or Zendesk (not Dynamics)
- You want month-to-month flexibility
- You do not want Microsoft controlling your comms + email + productivity
VestaCall also offers a Teams integration option — you keep Teams for chat and video but route calls through VestaCall for better quality and call center features. Best of both worlds without the compromises.
