3CX vs Zoom Phone: cheap entry, careful pricing.

• Metered — £8.07/user/mo. Includes the Zoom Phone licence but NOT calling minutes. UK landline / mobile calls billed per-minute (currently ~£0.024 to UK landlines, ~£0.10 to UK mobiles at standard Zoom Phone metered rates). Easy to overspend if usage estimates are wrong.
• Pro — £11.84/user/mo. Includes unlimited UK domestic calling. The realistic SME tier.
• Pro Plus — £18.59/user/mo. Adds the Zoom Workplace suite and AI Companion features.

The Metered tier looks cheap on the headline. In practice, a UK SME with 25 users making ~30 minutes outbound to landlines and ~10 minutes to mobiles per user per day pays an extra ~£100–150/month over the Metered headline — roughly the difference between Metered and Pro. For most firms, Pro is the right pick.

• Zoom Meetings integration. If your firm is heavily Zoom Meetings-centric for video, having calling in the same vendor is a coherent stack. Same login, same admin console, same support.
• Cheap entry tier (Metered) for very-low-volume usage. A 5-user firm making 10 calls a week genuinely pays under £50/month on Metered. 3CX SMB FREE is also under £50/month (free, in fact) but requires DIY setup.
• Polished UX. Zoom's product design is well-regarded. Calls in the Zoom client work the same way Zoom meetings do.
• Global presence. Zoom Phone is in 47+ countries. UK-based firms with international footprint get coherent single-vendor coverage.

• Pick Zoom Phone if: you're heavily invested in Zoom Meetings, you want a polished out-of-the-box UX, you're under 20 users with simple needs, or the Zoom brand simplifies procurement.
• Pick managed 3CX if: you need PBX depth (queues, recording, IVR), you care about TCO above 30 users, or you want a UK partner relationship.
• Pick Metered (carefully) if: you have genuinely-low call volume (under 5 min/user/day average) and want the cheapest viable option. Monitor the bill monthly.