I'm in a similar position now but the prices on the r350 and r320 are in the $26-$30k range for under 40,00 miles. I really like the styling of the cars and room, but I am very worried about reliability. I am coming from a 199 Infiniti QX4 which I have driven 160k miles replacing only the distributor and air compressor (I did replace a timing belt as a preventative).

I'm between the Mercedes and GMC Acadias which on average is a couple of grand more than the Mercedes. Aside from the better gas mileage (not so much over the diesel), I have never owned a German car before and the Acadia I am sure will be chaper maintenace wise. I am most concerned about reliability, I don't want my wife to be on a 4 hour trip to see the In-Laws and break down. I have been out of the car market so long I have no clue about vehicle reliability for most anything out there. Toyotas and Hondas still have the reputations, and while that is the extent of my "knowledge" the Acadia just seems like the vehicle that might be more reliable.

I'm not opposed to an extended warranty, any idea what one would cost, and do MB dealers typically offer/sell them for cars purchased elsewhere (internet)?

Bob,
That seems a little rich. In Dallas it would go for the low $30K range.

I own a 2006 R350 with a little over 33,000 miles currently showing on the odometer. So far, it has been trouble-free.

Just returned from a 2,300 mile trip to Wisconsin and back and got anywhere between 25-26 miles per gallon, which is pretty good for such a large/heavy vehicle.

I also own a 2000 ML320 with 82,000 miles on it which has also been very reliable and trouble-free. Over the last 13 years, I have owned a total of 6 different Mercedes Benz vehicles (including the two above) and have been very satisfied with all of them. Currently, I also own a 2009 C300.

Once you have driven a Mercedes for any length of time, it has hard to go back and drive anything else.

Our newest car (E320, 1998) now has 168km (100k_ miles) and although it has no issues, I have been thinking about buying a newer vehicle for the LD trips. Or other cars are an '85 300D and a '72 350SL both of which we have owned for over 20 years.

An R-Class CDI is a front runner. Here in Canada, dealers want $40k plus for them, but there are many on the market in the $33-36k range (Cars here are more expensive than in USA). Or local dealer want $43,900 for a 2007 with 59k km on it (35k miles).

I also looked at diesel Jeep Grand Cherokees . They are in $28k-$36k range and have a Benz designed engine.

But those prices are in the range of a new Japanese or Domestic car. Because I want something that will carry our golf and sailing stuff, I do want a crossover type vehicle. Honda Crosstour comes to mind. They were supposed to have one with a diesel, but no sign of it yet.

As a dyed in teh woll Benz owner, it is hard to buy something else, but we did buy a new Tahoe in 1995 and enjoyed owning that.

I ended up trading the R320CDI on a BMW wagon that my wife started driving.
I got $19K on the trade in back in 2012; this is the main reason I haven't been posting here very much the last few years.
My 16 year old daughter wants my Honda minivan, still going strong with a lifetime XM subscription and the premium sound system.
I am drawn to a local 1994 E420 in the color I have a weakness for, I think it's code 777 Beryll Blue.

I don't know if this helps, but I bought a 2005 E320CDI with 107000 miles from a M-B dealer in 2010: it has 150,000 miles now, trouble-free. It uses no oil between changes (12,000 mile interval) and I am well pleased with it. Paid $15,499.