zzr 250 isnt such a small bike, i rode one on my l's p's, ofc i didnt go hard at all and always stuck to speed limits (truely), unfortunately i cant say that now
Comparing it to other entry level bikes, the hyo gtr 650 weighs like 200+ kgs compared to the 150~ kg of a zzr 250. im pretty sure the 650s power is also comparable to the 250s and with 200kg its gonna feel like a massive bike, the 10R feel heavy enough at 180kg.
Depending on how fast you are going to get a new bike-(usually its alot quicker than you expect) a older model zzr will hold its value alot better i bough mine for 3k and sold for 3k 1 1/2 years later. Once your unrestricted you probly want something like a 600 sports bike or bigger, so if you lose alot on resale it might not be the best thing. 250s dont have THAT much power, they will get you from A to B easily at the speed limit, no 0-100 in 3.2s though

i felt i learnt alot from mine, riding position is more forgiving becuase there is less pressure on your wrists from more upright position compared to a 'sport' bike, so mistakes with the accelerator wont lead to kissing the tarmac that quickly.
You will have fun on anything, even if its a postie bike ( sometimes i have more fun on the postie than the zx-10r

)