It really does come down to personal preference, however, we would say the following blasters are our personal favourites:
RIFLES
TT MKIII (High End) - https://www.tactoys.com.au/products/tactoys-m4a1-mkiii-gel-blaster-stage-3-comp-ready
M4A1 V8 (Entry Level) - https://www.tactoys.com.au/products/m4a1-v8-gel-blaster
PISTOLS
3DG Glock 17 (High End) - https://www.tactoys.com.au/products/3dg-glock-17-gen-4-gel-blaster
Beretta M92 (Entry Level) - https://www.tactoys.com.au/products/skd-beretta-m92-14-8v-gel-blaster