"I've been told be some that it will be
just fine, and others who say no way!"
The folks who warn against aluminium boilers
need to take a physics course.
The ONLY way anything can get from the boiler to the collector
is by being first vaporised and then condensed.
The boiler is operating at 100 degrees Celsius AT MOST,
while the boiling point of aluminium is 2519 °C.
Ain't gonna happen.
You might remind your well-meaning but uninformed advisers
that this is exactly WHY people distill their drinking water,
to leave salt, bacteria, and metals behind in the boiler.
Enjoy your drink, it's as pure as can be!