Almost all e-lockers can be ill-tempered, and at times, truly obstinate. Even if you try to engage them on flat ground with your wheels pointed straight. I think the e-lockers in the Power Wagon are the worst, followed by those in the Jeep Rubicon. The best e-lockers in the North American market - by far - are those in the Ford Bronco. They lock instantly.
I despise all electronically activated features in a off-road focused 4x4. The dial-controlled transfer cases are often as annoying as the e-lockers when you are trying to get into low-range.
In my opinion, the analogue solution is always the best: manually controlled transfer case using a lever (like that in the Grenadier), and manually activated lockers, also using a lever attached to a cable, which runs to the differential. There are not a lot on the market, but see this as an example:
OX Offers a variety of locking differentials and other accessories, boasting some of the toughest products on the market.
ox-usa.com
A separate issue with the Eaton e-lockers in the Grenadier, is that they unlock briefly when you shift between forward and reverse (and vice-versa). This is not optimal, and may result in difficulty getting unstuck (if you are stuck). Air-lockers, like those from ARB, and the manual locker from Ox (mentioned above), do not disengage when shifting between forward and reverse, or vice-versa.
My personal preference: I would have been much happier if the Grenadier came with a Dana-style axle, for which there are numerous options for lockers (including Ox, ARB, and many more). Had the Grenadier come with a Dana axle, I would not spec it from the factory with e-lockers, I'd put in some Ox lockers myself, and have a more analog rig. I really hope that the aftermarket steps up to work with Carraro, but I'm not going to hold my breath for that. So I will - reluctantly - order the Grenadier with the Eaton lockers.
I've posted this link before, but here is a pretty good review of all the major types of lockers:
View: https://www.youtube.com/watch?v=x40WGUtdaLI