VoiceFlex Flow vs Gamma Horizon: Which Should You Choose?

VoiceFlex Flow and Gamma Horizon both replace an ageing office phone system with one that runs over the internet, but they suit different teams. Flow is built around Microsoft Teams and shared communications tools, while Horizon is a simpler, handset-friendly hosted system with UK calls bundled in.

The short version: if your staff already live in Teams, shortlist Flow. If you want phones that ring, transfer and get out of the way, shortlist Horizon. Prices below come from the T2K Voice & Data system pages and are per user per month, excluding VAT.

Which one suits your business?

• Pick VoiceFlex Flow if Teams is where your people already work, you want chat, video and calls in one app, or you run a busy sales or support floor and want live dashboards.
• Pick Gamma Horizon if you want a hosted phone system with a handset included, unlimited UK calls (subject to fair usage) and a short list of features that rarely change.
• Look at neither if you need a deep CRM link or heavy customisation. 3CX is usually the better fit there.

How do the prices compare?

Don't compare the cheapest Flow price with the cheapest Horizon price. Flow Basic leaves out the apps, so UC at £11.99 is the fair match for Horizon Essential at £12.95. Horizon's free handset needs a 36-month term. Flow's page doesn't state contract length, set-up fees or a minimum number of seats, so ask T2K to confirm those before you total anything up.

How does each one work with Microsoft Teams?

Flow runs as an embedded app inside Teams. According to the product page, it supplies PBX voice features without a Microsoft Business Phone licence, and presence syncs both ways. Horizon connects through Direct Routing, so calls travel over Gamma's network instead of Microsoft's. Both give staff a Teams-based way to take business calls.

If you're still weighing up Microsoft's own calling plan, read Microsoft Teams Calling vs Gamma Horizon first.

What do you get for calls?

Horizon includes unlimited UK local, national and mobile calls, subject to Gamma's fair usage policy. Flow lists a monthly allowance by package: 500 national and local plus 500 mobile on Basic, and 2,000 of each on UC, CC Pro and Flow Operator. The page doesn't say whether those figures are minutes or calls, and it notes that inclusive usage is subject to fair usage, so get that in writing. A team of 30 on long customer calls can use an allowance faster than you'd expect.

Which is better for a busy queue?

Flow CC Pro (£16.99) costs about the same as Horizon Office (£16.95), and the Horizon agent licence needs Enterprise at £24.95, but the features differ. Flow CC Pro brings live dashboards, call back in queue and wrap-up time. Horizon adds queueing from Office and the Call Centre Agent on Enterprise. Ask for a demo of the queue screens with your own call flow, not a generic one.

Where does each one fall short?

• Horizon: it's cloud-only, CRM integration stops at screen pop and click-to-dial, and configuration is limited to what Gamma's platform allows. Call queueing and recording need Office or above.
• Flow: the Basic tier is thin, recording is only mentioned as an on-request add-on for Basic, and the contract terms aren't published.
• Both: they depend on your internet connection. Plan roughly 100 Kbps per call each way, and consider a second line if a dead connection would stop trade.

What does this look like in practice?

Picture a recruitment consultancy in Poole with 25 staff who share candidate chat in Teams all day. Flow UC keeps calls, chat and presence in one place, so a consultant sees a colleague is on a call before transferring to them. Now picture a Dorchester accountancy practice with eight people, a reception desk and a January rush. Horizon Office gives them queueing and recording without asking anyone to learn a new app.

Both are illustrations, not quotes. Your answer depends on call volumes, handsets and how many people work away from the office.

Frequently asked questions

Is VoiceFlex Flow cheaper than Gamma Horizon?

Flow Basic (£7.99) is cheaper than any Horizon package, but it excludes the apps. Compared like for like, Flow UC (£11.99) sits just below Horizon Essential (£12.95). Check contract length and call allowances before deciding.

Can Flow replace Microsoft Teams Phone licences?

The Flow product page says the embedded Teams app provides PBX voice features without a Microsoft Business Phone licence. Confirm what your current Microsoft plan covers before you cancel anything.

Will either one survive the PSTN switch-off?

Yes. Both run over the internet and don't use the copper network that closes on 31 January 2027. Run the PSTN switch-off checker to find out which other services on your line, such as alarms, still need attention.

How many users does each suit?

Flow is aimed at 10 to 500 users. Horizon starts at 5 users. If you're below 10, talk to T2K before assuming Flow is available at your size.

Can we keep our existing phone numbers?

Generally yes. Numbers can be ported to either system, and T2K manages the move so there's no gap in service. Ask T2K how long your particular numbers will take.

Compare them against your own call flow

The VoiceFlex Flow review sets out its strengths and limits in more detail, and the best business phone systems guide places both among the alternatives.