After having some success with charging a semi dead marine battery and a couple of vehicle batteries, this charger has simply stopped working. It never did seem to operate correctly, having a mind of its own. Sometimes I'd plug it in and it would work, other times it wouldn't. The internal cooling fan would quit working midway through a charge and the unit would get very hot. Unplugging it and plugging it back in again didn't help. After all the hype from their advertising I thought I was buying a quality charger, but its not the case in this instance. I'm not unreasonable and understand I may have received a faulty unit, but the seller said .. contact the manufacturer for warranty replacement, and the manufacturer has done nothing but send an auto reply.. "we will get back to you, usually within 24 hours"... its been a week and nothing.
This is the beginning for me, I wont give up easily. $300.00 is not small change and I'd like my money back or a working replacement.
Its less than 11 months since purchase, its charged all of two batteries and its supposed to be covered under a 2 year warranty.
If this gets resolved satisfactorily, I will certainly amend this post.

I've had this unit in regular use for almost a year now, and it's kept all my batteries in fine fettle, whether they be small motorcycle batteries, or the DieHard Platinum batteries running in a dual-battery setup in my Tacoma 4X4 rig. These batteries are five years old now, yet they still hold around 13V after the surface charge has dissipated. In fact, this CTEK unit is one of the few aftermarket chargers recommended by Odyssey for these batteries, as it supplies enough voltage and amperage to keep the Odyssey/Platinum batteries properly maintained.

These batteries get a workout on overland trips running a fridge-freezer, stereo, lights and device-charging in desert trips to Baja and the southwest. In a few instances, when I've neglected to deploy my 100W solar tie-in while camping (my bad), the auxiliary battery has gotten down into the low-11V range. In each case, the CTEK seems to have restored the system to the performance it previously had.

The unit seems to be well-constructed, and in particular, the power cord and battery leads are very robust and seem to be of the highest quality. I'll be looking to purchase one of the smaller CTEK units for my motorcycle since the Noco Genius G1100 I was using just gave up the ghost!

Big, heavy and powerful. Too powerful to use with the comfort extensions. LEDs are nice "user entertainment" feature. I use it, among other things, to top off the two batteries in my diesel pickup without having to disconnect them.

There's lots of good quality battery chargers in my shop, but none is really my favorite. They all have some different advantages for particular applications. My CTEK MUS 25000 is a very early model, maybe 8 years old, it even has the XS European label. Unlike the smaller CTEK chargers, the 25000 has a thermally controlled ducted fan that's fairly quiet. Also it does not have the snowflake setting (that increases the voltage limit from 14.4 to 14.7) -- Instead it uses a temperature probe attached to one of the battery clamps to trim the voltage up or down proportional to temperature. This has advantages and disadvantages: One can't manually select 14.7 for a slightly faster/better charge on certain AGM batteries, but it also eliminates potential user selection error. The voltage accuracy is excellent, and it does put out a full 25 amps. There is a selectable reconditioning mode raises the voltage at the last period of charging to ~15.7 volts, and there are the appropriate warnings in the manual about higher voltage during the reconditioning phase -- Best be careful not to select this by accident even though in most situations it won't damage a battery or automotive electronics (emphasis on the word "most").

It's a good all around quality charger for all automotive AGM and wet cell batteries. 25 amps is a good middle of the road rate, not as much as most car charging systems, but proportionally faster than the common 3 to 15 amp plug-in chargers.

I've had a few different chargers. My first was a manual 2/10 amp, I think it was a sears. That thing barely worked. Next was a schumacher, I think 2/10/25 amp auto shutoff. That one I loved until it got "borrowed" by my idiot neighbor. Next was a vector, I think 2/10/25 with 75 jumpstart mode and desulfate mode. It worked great until it got stolen. Next was a black and decker which looked exactly like the vector but didn't work nearly as good and eventually wouldn't work at all.

After the b&d died, I really spent time to research to find another good one. For some reason, there are several models not for sale in california. This is frustrating because there are several good ones out there that I can't buy. After doing without and a long search, I finally broke down and dropped the dough on this ctek.

I havent had it for very long but the times I used it it worked good. I do wish it came with some sort of storage case or at least a good box to store it in.

5/22/16 update:
Many times I've taken a borderline failing battery, charged it up, then ran desulfate, which saved it if it would finish the desulfate cycle. If it won't finish, nothing will save it.

Example my fathers 21 year old truck with just over 30000 miles, meaning he barely ever drives it, really not often enough to keep the battery healthy. I ran charge, then desulate due to slow cranking. Now it just passes a starter voltage drop test and seems to be doing fine.

Another example, battery about 1 year old, they ran it down to 8.5v cranking a no start. Same charge and desulfate cycles. I left it cranking strong, easily passing the starter voltage drop test.

Overall, I'm happy with it. What I learned is that California prohibits the sale of a battery charger that continues to consume power after the battery is charged. Thats why several models can't be bought here.