one very good place is clock tower imo. clocks are slow and give good exp. just dont forget firewall.
there are a few ridewords and mimics which can be annoying though. alarms are also good kills, they give good exp. if you can work out the weird warps to get there.
if you like, you can also kill seals, but they are more troublesome because of the number and the other things that are agro there. not as annoying as clock tower but less exp than alarms.
those guides are too generic btw, those builds are ok but i suggest if you want to be good, make your own build rather than stealing them from there. I begun as the sacrifice sader using that build and decided i don't like gc and i don't need shield charge, so i got rid of what i don't want and go for the one i wanted.
the stat there is also too typical, just watch out for some of them cos there are quite a lot of stupid ones out there. there i one i came across once with some guy proposing to get lvl 3 everything so he can use every element for wizard. let me just say that lvl 3 defensive skills don't last long and are pathetic and the attacks are weak.
that was the stupidest build i ever came across actually. with the guy sugesting dex for instant cast, and equal all the other stats excluding luck. his reason was :
str to carry those blue pots

agi just to dodge some monsters and reduce stun time when hit by monster

vit for hp

int to do damage with

dex max out for instant cast
well imo, he could spend that agi and str on int if he max out sp recovery and lower vit cos if he can instant kill a monster he won't have a problem being hit. the fast cast i agree with but the rest is just rubbish.
::Edit:: just adding emoticons