Look, either or any boiler will give you the heat you require.
I work for Vokera, all I am allowed to do is tell you what the product can do then you can compare it with others.
The Vibe Max will have an output of 30kW for hot water and 25kW for heating but the heating output can be range rated to any output down to its minimum of (3.8kW) matching the requirement of the property.
It has soft start meaning it will fire at 60% of the range-rated not it's maximum output for the first 15 minutes before increasing output in 10% increments. Why is this important? Well, the world will not stop turning if a boiler comes on and cycles trying to put in more heat than the property can absorb but as the vast majority of restarts are with an already warm system and not a stone cold one it makes a more adaptable starting sequence.
As an addendum to that the anti- cycle delay is adjustable to 20 minutes meaning it can be lengthened from the factory setting of 3 minutes to reduce cycling further.
The pump is modulating of course but in addition the pump duty cycle can be adjusted to the requirements of the system avoiding over pumping. Why? Most systems need around 1-1.5 metre head to overcome resistance; your system will require around 400l/hr with an ideal ∆T of 20⁰C across the F&R. Even though the pump is already set at 85% of it's output from the factory that will still result in over pumping by a factor of 3-ish and narrow the ∆T (the wider the better). Who cares? If you don't, don't worry, you'll be just as warm while the boiler cycles unnecessarily
The boiler can be controlled Open therm which the EU reckon is a 4% saving over an ON/OFF thermostat or by dual temp weather compensation which is reckoned to be a 2% improvement.
Other things of less importance; the optional Wi-Fi key offers remote access to boiler pressure etc, downloads external temperature from the internet for the WC as well as a year warranty extension. There's the included Bluetooth timer, handy if you use dual temp WC. Smart hot water preheat plus two other preheats and if you ring 01727 744002 they'll give you the names of installers in your area.
It's up to you but there's something there to get your teeth into.
The glow worms heated a house up properly, these modern boilers dont. If you haven't experienced the glow worm era and just are one of those heros that completed a 6 week gas course then you wouldn't understand as you're all about profit and "recommending new boilers (a combi as the wiring is easier) under the energy efficiency nonsense"
What if I started installing boilers in 1976 and have done so until present?
What if I'd been involved in thousands and thousands of installations and now include heat pumps?
Then again I could have gone to builders merchant and asked counter staff who hadn't actually installed a boiler what boiler they'd choose not knowing what offers of counter cash or incentive that branch might be getting from a particular manufacturer.
