>>53564821 I cannot speak for GSC since I haven't played them since I was a kid, but for HG/SS its boring as fuck.
terrible wild lvl encounter rate. lvl 15 pokemon outside 7th gym leaders town. evolution stones aren't available at dept, store. most come from your mom and people you give phone calls too.
The types of encounters you find are also boring. half the gen 2 pokemon are locked out until post elite 4. Half the pokemon you encounter are gen 1 mons you find before the 3rd gym in FR/LG. finding rattatas outside of the 6th gym leaders town is stupid.
other than being starved for levels, there really isn't any challenge. the only 2 memorable gym leaders I can think of are whitney and claire. Whitney purely because her Miltank is just annoying, recovery, flinch, attract and a lum berry makes it a slog to kill. claire's kingdra simply for little to no type advantage pre fight. you can take care of her dragonair's easy enough with an icefang Gyrados/Feraligatr, but you won't get any real effective dragon moves for kingdra, so it makes her more of a threat.
the rest of the gym leaders are hot garbage