Opinion Please !

mercedes spends more time in teh shop then any other engine. they are expensive to fix. and not very mechanic friendly.

the volvo engine would be a big upgrade. and that's not saying much.

 

my experience with MB were ok but in general you would want to consider a detroit over a MB, they are more expensive to fix and parts are harder to come by. they are also owned by Daimler Chrysler as are Freightliner, Western Star and Detroit so theyre all crossovers in the brand.
My typical rule of thumb is if its a freightshaker take a detroit, western star take a detroit or cat if its older truck, pete and KW take a cummins or cat. volvo and international take a cummins. these combos just seem to work from what I have seen in my tenure.

 

Having actually owned one since mid 2005 when I took delivery, I may be able to shed some light.
I am plated at 117k lbs.
Does the MBE pull like my old 585hp Detroit or 550 Cat? Obviously not.
I have had my grubby little mits into most motors out there, 3406's, C15's, N14's, Volvo's, S60's and so on. The MBE 4000 is a complete walk in the park to work on out of all of them in my opinion. Sure some have very easy parts to get to, but for the most part, and most routine servicing, the MBE is easier.
Does it constantly get better MPG pulling the same loads, than anybody else? Sure does.
They are, in fact, easy to work on. The newer Dd's are laid out the same way now, with the timing gear in the rear of the motor. So no advantage there anymore. The heads are individual, and are a piece of cake to replace, but the newer style HG and heads have cured the vast majority of issues with them.
Parts are available at any Freightliner or Detroit dealer, and have yet to have any big issues getting parts myself. I do a lot of work myself, thus can comment from actual experience and not from internet gossip.
They way a lot of stuff is laid out on the motor makes it very user friendly indeed, and have yet to have anyone not be able to repair it etc if I am out on the road. they are more than common enough to be a known quantity now. They are also very light weight, which makes me more $$ by lowering my empty weight.
There are a few of us on here that have installed tuners etc, which work very well thus far, with MPG also going up, along with the HP.
Martin

 

Run hard run fast.....away from that engine

 

I have driven a MBE powered truck for several years now.
It lacks power, as an automatic. The standard trucks I was driving previously, were somewhat able to hide this lack of power by staying in the band longer.
Mine does very well on fuel over the average trip distance.