One hour, dual to solo was all I needed back in 1969 when I converted to the Cherokee 140 having only a few hours on gliders and 35 hours on the Cessna 150 before then - and I hadn't flown at all for nearly a year when I did so. Allow a bit more time if you choose to convert to a wobbly-prop version.
There is more space in the PA28 than in the C150, particularly in the Warrior.
The control harmony of the C150 seemed nicer, the PA28 is a little firmer on the controls in general. I was lucky enough to have done my PPL on brand-new Reims-built C150s; my experience of the US-made version was that the interior was rather flimsy and the PA28 interior is considerably more robust.
Doors on both sides can be a distinct advantage when flying with passengers!
Both have their pros and cons, but there's no obvious winner except on the grounds of operating cost - the C150 is considerably cheaper than the Warrior.