Dramatically lower pricing

Modulo Pro

Price User/Month
(Billed Annually) 
$1.99$2.99

After 9 free users

Zello Work

Price User/Month
(Billed Annually) 
$6.80
+
$3.40*
$8.00
+
$4.00*
*For admin management of historical messages

Voxer Business

Price User/Month
(Billed Annually) 
$8.33$9.80

Live and historical 'breadcrumb' location-mapping functionality included free

On-premise infrastructure available with the same pricing (for 200+ users)

Admin management of historical messages available as premium function

IP-Radio Gateways charged separately, and gateway hardware required.
VoiceLayer-tested gateways and rack-mounted-gateways