The lower level version has had some more attention since it was revealed earlier, and at level 2, has a lot more people able to take it, including any subclass Rogue, Akachi and Ursula. At 5, even Finn misses out on it, poor guy.
At 10 exp for one copy, it's hard to say what would be worth that. Even the Key of Ys doesn't really feel worth it at 10. But The clock does have one big advantage over the key; it can be upgraded from a 4xp card. So really, it isn't so much a question of "is it worth 10xp to buy?", but "is it worth 6xp to upgrade?", to which I think the answer is yes, if you can find the time, or afford it.
Compared to the level 2 version, it's the same cost, adds an icon, and all the numbers on the effects go up by one. +4 instead of +3, move 3 times instead of 2, and take 2 extra actions instead of 1. None of those are bad at all, but certainly wouldn't be worth 6xp, let alone 10. The big, hugely important change, though, is the timing point of removing charges. Instead of choosing to take or place, then checking, you get the option to take the charges, then always place. This means it ramps up to every effect one turn faster after the first cycle, and gives you an effect the turn you take its resources. These are pretty huge changes.
The Red Clock (2), if used for each climbing effect is essentially: Turn 1, get a +3, Turn 2, move up to twice, Turn 3, get an extra action, Turn 4, gain three resources. In comparison, this version is: Turn 1, get a +4, Turn 2, move up to three times, Turn 3, get two extra actions, Turn 4, gain three resources and get a +4, and continues so on. So if you use both in the simplest possible way, this version will give you a lot of extra value over longer games by simply getting the turn 3 and 4 benefits together. Is that alone worth the 6xp upgrade? Well, maybe. Generally would depend on how early you can get it into play, since you aren't actually getting much value on the first cycle, other than increased numbers.
However, the timing point changing offers a more versatile way of using the Red Clock. Instead of ramping it up, you could simply take the resource every time, giving you a guaranteed resource every turn, and +4 to the first test you make every turn. That's a very solid effect by itself. Or, you can intend to do that, and then on turns where you aren't likely to make important tests but need to move, take the move. Then after that, you can check whether you need resources and a test bonus, or extra actions. The point is, it's a lot of versatility, and you can pretty much always use one of the abilities.
Of course, there's also the argument that the real exp cost is neither 10 nor 6, but 13 (or 9), since Relic Hunter is a very important consideration for the class with such great accessory slots, some of which you'd want to try and get the Red Clock as early as possible anyway. But then we can say it actually costs 19, since you want two Cigarette Cases alongside the Relic Hunter, and that's a whole Rabbit Hole I don't want to go down. (Speaking of which, it doesn't even save exp since you pay 5 then 5 instead of 4 then 6. How sad.)