Well... to start I will comment on H&K amps. They have a pretty distinct sound to them... well... most of them I would say. Especially their tube amps. But, this model is a solid state amp and its only 15 watts so you're not going to hear much of a difference. I would say play it before you pay for it though... thats a general rule about all music gear aside from various pedals and such...

You don't neccessarily need an effects loop input for your amp... its just a break in the circuit that general keeps the guitars tone intact a little better. BUT I doubt you're planning on running a huge effects set up into a practice amp... I practice with a little 8 watt amp with a cheap rp-80 hooked to it and it does just fine for what i need to practice. If you want something that you're going to gig with... I would suggest something up in the range of 50+ watts... which most certainly should have an effects loop in it.