Which I mentioned, incidentally, in the same post I did the comparison.....
However, they can be broken in the other direction, if you have Leadership, Epic Leadership, or just lots of time.
Consider: a 21st level Sorceror with Epic Spellcasting wants to be a Gold Dragon.
The Transform seed can do it all.
Base DC 21.
A Young Adult Gold Dragon has 20 Hit Dice, is size Huge, has two breath weapons, alternate form, water breathing, iummunity to fire (crafting your own spell, it's potentially possible to skip the Vulnerability to Cold....), DR 5/Magic, seven natural attacks (one of which is Ex), Frightful Presence, Immunity to Sleep, Immunity to Paralysis, Spell Resistence, Blindsense, and Keen Senses. Two size categories up from medium: +6 DC; type change, +5 DC; 5 hit dice above 15: +10 DC; 14 Ex/Su abilities: +140 DC. It's already permanent. So, we have a base Spellcraft DC of 21+6+5+10+140=182, base.
Now we mitigate: Personal: -2; Extra 10 minutes: -20; Now, adding 80 days, 160 first level spell slots in a ritual, 54 2nd level spell slots, 32 3rd level spell slots, or some combination thereof will drop the DC all the way down to 0 (and a Sorceror with Leadership can likely arrange that fairly easily).
And then you have the Permanent ability to ignore a fairly long list of effects, change your form three times per day, use two types of breath weapon, fly, and such. For 0 XP and 0 Gp.