some folks in the know say that Tomahawk needs bit of an input to get out of spin (not necessarily bad thing I guess)
Unlike 152, as mentioned, that it straightens itself out = read as let go (unless panicked student pulls the yoke to his/her chest, read about a fatal on PPRuNe where this was presumed cause of accident with instructor - lesson to learn, don't fight the instructor if crapping own pants - that is, if onboard)
Considering it's 8/9% difference respectively - your prospective school has either pricey 152s or cheap 172s, not sure about OZ pricing.
Most schools in the US have 15-20 bucks difference in hourly rental (80 - 100, or 100ish vs 120ish), so it makes a difference to fly 152 unless 172 needed for IR training. UK ditto, but in GBP.
Not to mention SP or G1000 thingies, those 172s could be 50-70% more than 152 in some schools.
For that small difference, I'd fly about 30% of initial hours (or whole PPL) in 152 and then went on 172 for the feel and instruments etc.
As mentioned, teaming up with fellow students for some 'mutual observation' in 172 dual flights is good for learning.
Shame I counldn't fit in R22 when did some rotary flying (tight with stude and CFI already)
The school wouldn't allow 'observing passengers' pre-PPL issue of the student in command anyway, plus I think 70h TT or so min, too.
I only fly gliders now and then, but when back to intensive flying (subject to cash and time) I'll learn in taildraggers a la Cub for very own reasons. Then whatever for IR rating later on.