He's gone past Donald's wicket tally now and id still have him about level with him. Just a personal preference, i just like bowlers who swing it both ways consistently. Steyn does have an inswinger (bowled a couple of crackerjacks in his 7 for at Nagpur iirc) but he rarely brings it out these days. Seems to instead prefer the in seamer without actually swinging it in too much.
By the time he retires, barring some ridiculous collapse in form, he'll probably be South Africa's greatest bowler ever.
That said Philander is getting truly ridiculous now and he will most definitely be up there with the greatest too.