Diamond
Frankfurt Airport
Booked IDMR (Ford Mondeo)
Got a Merc C220 Diesel - which has been absolutely fine

Frankfurt City East (Hanauer Landstr.)
Booked FDMR (3series BMW)
Got offered a Merc E200D, which I declined (136 hhp)
Next offer made was a brandnew Merc ML 350 together with an upgrade surcharge of 180 € / week
After a long discussion forth and back, they finally found me a BMW 525d,
that according to the agent did not exist five minutes before.
Imho, Diamond status has seen better days.

No Status
Madrid Nuevos Ministerios
VW Polo
Opel Isignia

Very nice upgrade, included Sat Nav and had 1,500km down, so almost fresh out of the factory.

Going again on Friday, let's see what they offer me this time (reserved a BMW1 or similar)

Status: Diamond

Berlin Reinickendorf
Booked LDAR (BMW 5 GT)
Received: XFAR (BMW X5 4.0 Diesel X-Drive)
Very nice car with lots of torque, it is an upgrade, and I didn't have to drive around in a hideous looking car like the 5GT. As Sixt Berlin North is very small I didn't even ask for something else.

FRA
Booked: CPMR (BMW 1 series, Golf GTI, A class)
Received: Audi A4 Variant 2.0 TDI
Nice car for cruising on the Autobahn

Status: Platinum

Zurich to Munich (one-way)
Booked IWMR (Skoda Octavia Combi)
Received: FFMR (BMW X1)
Great experience in Europe, I can't wait until Sixt gets larger in the US locations. Cool little SUV/CUV 6 speed diesel with great fuel mileage. Almost got an X5, but there was a Diamond member that was already assigned to it.

Status: Platinum

Paris Saxe Invalides to Paris CDG
Booked FDMR (BMW 3 Series)
Received: FDMR w/ Navigation (BMW 3 Series Diesel)

Great experience in Paris, friendly customer service. Car only had 10 KM when I picked it up so it was fresh from the oven, they even washed it before I drove away. Saw a BMW 5 series there, but was not given one, not sure if that was reserved by someone else.

Status: None. I carry the Platinum card but didn't rent enough to qualify for upgrades.

Düsseldorf Unterrath Maritim
Booked CPMR/BMW 1-series with Nav
Received Audi A3 with NAV

Not sure if this is an upgrade but the A3 was fun to drive and the built-in NAV was great.

Hamburg Reeperbahn
Booked XFAR/BMW X5
Received XFAR/BMW X5

Was hoping for an X6 but was happy with the X5 4.0d. Got almost all the trimmings except for the adaptive cruise control. The vehicle has the rear-view camera with the dynamic parking lines as well as an 360 all around view similar to Infiniti's offering as well as a panoramic roof. Great acceleration and drives like a 5 series instead of a SUV. The website recently replaced the X5 with the Touareg as the representative vehicle. I hope they still offer X5/X6/ML.

Dusseldorf KÖ Interconti Hotel
Booked CDMR with Nav
Received Subaru Forrester with Navi (rearview mirror)

Disappointed with this car (underpowered) and Navi. Seems like Sixt replaced the OEM rearview mirror with one with a Garmin attached instead of renting a vehicle with Nav built-in Screen is tiny (about the same size as an iPhone 4S screen)

audi A3 is kind of what you should get for CPMR
because Navigation included it is a mini-upgrade.

but most CPMR cars in Germany have Navigation...

Does anyone have any experiences with Diamond status recognition in MIA (both the airport and the Miami Beach station)? I'll be renting there (most likely from both stations) in April and would like to know whether to expect the usual upgrade and possibly additional benefits like fast lane pick-up.

DIA is honoured in US

I dont think they have fast lane pickup.

Pick up- Stuttgart Zentrum
Status- Platinum
Booked FWMR- Mercedes C class estate
Received LWAR- BMW 525 Xdrive Touring
Nice car with many extras,though I would have prefered a rear camera to soft close doors;-)
It was my first time at this location,it is very conveniant and central. As the cars are 2 floors down in a car park for anyone reading not so good with stairs there is a lift but at the front of the building away from the Sixt office. My compliments too, to the charming staff .
Will be back in a few weeks

Platinum

Munich Schwabing
Booked: ECMR (diesel request and extra driver)
Received: CWMR VW Golf Estate, Match trim, 2.0 TDI, black, and with nav (but weirldy, only for Germany).

Munich Schwabing
Booked: CLMR (diesel, auto and a reasonable bhp requested)
Received: FDMR Audi A4 Saloon, Ambition(?) trim, 2.0 TDI, silver, and with full nav.

Both cars were picked up at the same time for a road-trip. According to the agent, we were going to be getting the two Golf estates sitting behind the office, but (luckily) the second (petrol) one would have gone over it's Km limit. Was offered a 335xd for €20 extra for the rental, but declined. Slightly regret declining since I think those are excellent cars, but the Audi was more economical over 1,500Km than a 335xd could have been!

Interestingly, this was the second time I was given a car from a class higher than I am allowed according to Sixt.de, but was assured it was not a problem by the agent. I assume this is an operational decision which the agent can take at the hand-over time?

Excellent service, excellent cars and a pleasure to deal with the Schwabing station as always!

especially as it would have been a 335xi and therefore a petrol car and not diesel

Haha, quite right!

Could have sworn he said 335xd, but maybe I was wrong...

if you find a 335xd on the website of bmw, let me know

(hint: they dont even produce 335d, let alone 335xd)

Ah, no they don't...

Shame, would be nice!

Just as well I declined, looking at mietwagen-talk.de, it seems to have about double the fuel consumption as the Audi had!