The clutch works really well once it's disengaged; it comes back in beautifully progressively up the travel, allowing as much slip as you want / can control (without g-forces, it's harder to balance than real life, of course). It's only "digital" in the disengaging, as you push the pedal down - it reaches a threshold and it suddenly disengages. It does also disengage a bit too far down the travel, but that's easy to get used to.
What is difficult to get used to, however, is the selection mechanism and the built-in checks.
To get a gear you need to have no throttle applied and the clutch disengaged. If you miss, you need to deselect the gear you just tried to select and then re-select it with the clutch disengaged and no throttle applied; that is surprisingly difficult to do in the heat of battle.
Since, in a real car, you can tell that the gear didn't go in, because you'd feel it in the selector, I think it's unrealistic to require the player to reselect the gear when they don't get that same "haptic" feedback. Your hand is already off the selector by the time you realise you've missed. There is also discussion about whether wheelspin prevents gears from being selected; drifters in particular are disappointed by that.
I'd suggest the selection model be changed to constantly poll the gear lever position, and the game to continue to attempt to select the gear indicated by the selector, as long as it's not "selected" in-game. Then, when you miss, all you should need to do is dip the clutch, and it'll go in as long as the selector is where you wanted it to be (and the throttle is off, as applicable).
Additionally, the strictness of the throttle check on the selection process should be tailored to individual tastes. I.e. add an option for online / competition only that allows the throttle checks, etc. to be turned on or off (GT Academy disallows the use of the clutch by default, for instance).
To allow for parity, and for the same level of expressive feedback (e.g. sound) from gear changes, the clutch should be opened up to be mappable as a button control, e.g. for DS3 users. I think that would be well received, generally, because the game's sequential controls are a little sterile by comparison, ironically because they're so fast (in order to close the gap to H-pattern users?).
I was very impressed by the H-pattern selection when it debuted in GT5 Prologue, I thought it quite the step forward for the series, despite how subtle or inconsequential it might seem. I was disappointed when it was modified, although I understand the motivation for fairness - I just think options are a better idea, rather than blanket restrictions.