I'm a huge fan of 2d10 to put emphasis on character building. d20 has always felt way too swingy to me. Not just for skill checks, but for combat as well. Modifiers EARNED by characters, matter more when "Average" performance is more likely to happen than extremely poor/excellent performance. I made a heat map in spreadsheets to help visualize the difference. The vertical axis represents the Difficulty Class of the action (the roll required to succeed). The horizontal axis represents the modifier being applied to the action (based on associated ability/proficiency/status effects). The resulting number taken from the color shaded table shows the % of success. Highlighted yellow values are in the 50% range. And can be used as a control to easily tell on sight how the overall difficulty of dice rolls is changed when different dice are used. The shaded colors also help visualize the contraction in possibilities when using more dice.
[Linked Image]
*Note*: 2d10 chart is built so that a critical failure occurs when rolling (2, 3, or 4) and critical success on (20)