A breakdown of what a level in GUL is worth:
- Either ST+2 [20] or ST+4 [40]
- DX+2 [40]
- IQ+2 [40]
- Either HT+2 [20] or HT+4 [40]
- A Wildcard! skill at Att-2 [6] or +4 to a Wildcard! skill [42 or 48]
- Charisma 8 [40]
- An undetermined level of Wealth, eyeballed as being Very Wealthy [30], since you can use it to buy Very Fine gear (x20 cost), in essence.
That's a pretty wide range, anywhere from 6 to 48 points per level. Interestingly, that whole spread occurs in the cost of the skill levels. The variation is surprising, and problematic. Take these two "4 level" GUL chars and check out their actual cost in GURPS:
Abe: Normal ST, Normal DX, Weak IQ, Normal HT, Wealthy, four skills at level 1 [14]
Bob: Normal ST, Agile DX, Normal IQ, Weak HT, Charismatic, one skill at level 3 [156]
Seriously. You can have a 14-point PC adventuring in the same party as a 156-point PC, both built on the same number of levels. Now, that could be called a feature if you want, but it's not a feature of GURPS.
I'd prefer to have a set point cost per level in mind, and then work to try to hit that target. Being a little off is okay, but the spread needs to be tightened.
For example, what about a target of 35 points? That's doable. First, fix ST and HT so that Weak = 7 instead of 8. Then define the first level of a skill as giving it to you at Att+1 [36]. Further levels add +3 [36]. With those simple changes, you've now tightened up the value of a level so that its value is between 30 to 40 points without exception. That's a spread of 10 points instead of a spread of 42!