Some class abilities are better than feats though, the Paladin gets his aura at 6 for example and that's way better than any feat.
Is that a universally true statement? Are you certain?
I think I'd have to agree. The Paladin ability is an always-on ability that greatly reduces your failure chances.
If it's a save you are proficient in and you have your ability up to standard for your level then your bonus is equal to the opposition's bonus. (Usually. An enemy is proficient in his save inducing attack like you are proficient in that save so that cancels. And his ability, especially if an NPC is probably equal to yours).
In this event you only need an 8 to save as your bonuses and his bonuses cancel. Potentially, at level 4, the Paladin could have an 18 Charisma granting +4 to the save. Now, instead of failing 35% of the time you only fail 15% of the time. You've reduced your chance of failing by 57%. By 8th level the Paladin can have a 20 Charisma and now you only fail 10% of the time. That's a 71% reduction in failures.
Here is probably the worst case scenario. If you aren't proficient in the save and have a -1 ability bonus. By level 6 the opponent might have +3 proficiency and +4 ability. This means you'll need a 15 to save and must roll a 16 on the die. Instead, you'll have net +3 to the roll and only need a 12. Before, you failed 75% of the time. Now, you fail 55% of the time for a 27% reduction in failures.
Add a bless to the best-case scenario and you have a scenario where you can only fail a proficient save by getting a 1 on a d20 and a d4. That's 1/80 rolls or 1.25%.
To be really absurd you could have party members take one level dip in a Constitution proficient class (or just be a Constitution proficient class) and then go nuts with Concentration spells and basically never fail your check. Fun times!
So, yeah. I agree that the Paladin save aura ability is absolutely amazing.