Why there are no specification tables here
Product specifications change without notice. A comparison table copied from a manufacturer's site is out of date the moment the line-up changes, and a homeowner who relies on it makes a decision from stale information. The manufacturer's own documentation is current by definition, so that is where specifications should come from.
What does not go stale is the decision framework: the calculated load, the fuel available, the panel capacity, the siting constraints, and whether anyone local can service the machine in five years. Those decide the outcome, and they are the same questions every year.
Comparison guides
Each guide covers what decides the choice, the questions to put to an electrician, and where to verify the product itself.
What actually decides equipment servicing, five years out
A brand's reputation on launch day says little about whether a technician in your area still carries parts for it later. The more durable questions are: which local electricians and HVAC contractors regularly service this brand today, how available parts have been for models a few years old, and whether the manufacturer's warranty transfers if the property is sold. Those answers come from the electrician quoting your project and from other local owners, not from a specification sheet.