if it is for professional purpose UMAX is the way to go. They build excellent quality scanners.
If personal purpose is main use you can opt for HP as they also build very good scnners.
Chose largest (in paper size you can afford) also try to avoid ultra slim models.
BTW : A question :
for what purpose you need to OCR, i am also right now digitizing my documents through help of ocr software and and HP AIO. Do you mind sharing a few tips and trick online in IMs?