Well, I think if you skip the tomb on korriban (or can't enter due to being too neutral and also never get your prestige for that matter--like I did my first game ever in TSL), you only get something like level 26 or thereabouts.
Otherwise I just go flat out to the full 50. More feats and powers to play with. Except for some odd reason the whole immortality at 0 health in the tomb area with the unlimited exp loop stopped working once I put a simple mod in it. I myself actually think it has something to do with the inconsistencies of operating it with the patch on Vista, relating somewhat to TSL being one buggy mo-fo.
TBH, though, I'm not really sure why they'd make a Lv. 50 when in the game you can barely achieve half of that naturally.
Also, don't get caught without a prestige class, it sucks.
If you do consular or its natural progression and have not solidified your physical combat progression very well, Sion is VERY HARD.
We'll murder them all, amid laughter and merriment...except for the few we take home to experiment!
"I cant see S***! --YOU GO TO HELL!" --Tourettes guy