We originally used the character creator that came WITH every 1st printing PH. It suffered from being SLOW, incapable of handling character advancement, buggy and had data errors, and apparently was not especially conducive to ever being updated - though they DID patch it. WotC announced that they were going to create a big thing they were calling Master Tools that was going to be more like not just a character generator but a virtual tabletop. They bit off more than they could chew and that kept getting cut back.
Meanwhile, a few other free generators came along and the best (IMO) was PCGen (even if it was written in Java). PCGen was graphically plain (still is) but handled everything we needed it to for managing PC character sheets. I started to actually hate it somewhat as a DM because it was SO PERVASIVE that players just had no f'n clue whatsoever how to level-up their PC's without using it. Really that was 3E's fault for becoming so bloated. Certainly by 10th level or so, players HAD TO have PCGen holding their hands to walk them through the level-up process and make sure their PC's were up-to-date and accurate.
Then the whole Master Tools debacle was turned over to Code Monkey publishing and morphed into E-tools. PCGen was better and had been there first, and was free (still is), which certainly was NOT true of E-tools at the time and I'm not sure if you do still have to pay for it. If you happen to have E-tools, I'd say use that. My personal view nowadays is that if you need software to manage your character sheets then the game is outrageously too bloated and complicated. But, I'd still recommend PCGen despite not having touched it in well over 15 years.