I've owned a 1998 E300 for 4+ years now. I didn't purchase it brand new, but it wasn't very used, either. Mine has not been the most reliable car, but I think John's is worse

I've had some of the same problems as John, some he won't have, and some he hasn't had yet. Many of the early 210.025 cars had trouble with the transmission electronics - one owner I met had his fail in Austria during European delivery! Mine died in the much less exciting locale of Plano, Texas. This problem puts the transmission into "limp-home" mode - you're not stranded, but you can only manage 30MPH. I limped on over to the dealer - 2 miles away - and handed them the car. It was fixed under warranty, and has stayed fixed for three years. My main complaint here is that it hunkered down in the shop for 14 days while the part was manufactured in Germany, shipped to the US, had software installed, and finally wound it's way down to Dallas.

All was well for about a year. Then the car started running rough during cold starts and smoking a little bit. No other symptoms, and it only did it first thing in the morning. Being a diesel guy, I figured it was a glow plug on its way out, and ignored the problem. Eventually it set the check engine light. I dutifully hauled it into the dealer, where they replaced the glow plugs and the controller. Car was fixed right the first time, and has stayed fixed, but again squatted in the shop for ~10 days. They only had four glow plugs in Dallas, and had to ship in the last two.

Here's one which John needs to know about - he hasn't had this problem yet, but will. The car started surging on the highway - a little bit of power loss, then it would come right back. On our Christmas road trip last year, it didn't want to start after lunch. Finally got it going, though the surging was worse. Made it to our destination, and checked under the hood. Tons of air bubbles running around in the clear fuel lines. Promptly dropped the car at the nearest MB dealer. They replaced all the fuel lines and the MAS, which was throwing a code. (Deteriorated o-rings causing air leaks into the fuel system are a well known problem with the OM606 engine - at least to the indy mechanics, if not the dealers...)

Other than that, the CD changer died and was replaced under warranty, and I've had a burned out bulb or two. Soft issues such as alignment, brake pad wear, and tire wear have all been very good.

So it's now about five years old. In the time I've owned it, it's never failed to start and never failed to get me to my destination. It's been in the shop four times, which is a bit high. Of more concern is that three of the problems affected the utility of the car - they had to be repaired immediately.

Would I sell it? No, I don't think so. It's a great car in too many ways. It's under warranty for six more years, and it's paid for. Besides, what would I replace it with? Lexus doesn't make anything which interests me, the BMW 5-series has too cramped an interior. The only things which interest me are an E55, or perhaps an E430 with a Kleeman supercharger - and both of those are out of the frying pan, into the fire. Think I'll keep it.