Very big change as far as the carpet nozzle Goes. Main unit just changed color scheme and now has 2 LED lights. Click on the banned below to see more pictures and feature descriptions:

Hmmm - not sure why they came out with this one. Maybe just improving on the color scheme, maybe it is a marketing move but this is the same as the GOLD Rainbow E2 series sweeper.

Just 3 changes in accessories included:

1. Included in the set "Aerofresh Bag" in the set ) nothing special just a thick polyethylene bag with Rainbow logos on it
2. Instead of the bottom curved wand and regular 10 inch wide bare floor tool you get another straight wand and 12 inch wide floor tool with swivel
3. Electrified hose is redesigned and tripple-insulated so can be used to pickup water.

First came out in 2003. At first it does not look much different from prior e-series vacuum model however it actually is quite different.

1. New type "Hurricane" motor. This motor is pretty advanced and uses no motor brushes that fails in a lot of vacuums.Motor has a sensor that reads at what position is the rotor and tells it to a controller board. Controller board alternates current supplied to stator (field) so rotor gets/pushed/pulled by ever alternating magnetic field. There was a batch of these made with improperly forged rotor shafts but late manufacturer resolved the issue. Motor itself is not that expensive to replace (cost of the motor is around 100-150 in US market). Controller board (a.k.a. computer) is the most expensive part and will set you back by $240-$300 .
2. Carpet nozzle got redesigned several times over and the final result was a new type of motor and it is assembled using mostly plastic tabs that just snap in place and hold everything together. Pilot light (indicator light that tells that power is being supplied to the nozzle) and circuit breaker switch is not there anymore.

This is a totally different "animal".  New type of  motor with higher RPM (spins faster).  Has a bit better suction (not a lot).  Works more quietly.  Has a filter on the motor so motor does not get dirty even in a very dusty environment.  Has a HEPA filter cartridge on the exhaust for additional filtration.  On later e-series Rainbow vacuums, the manufacturer installed a "washable" HEPA filter cartridge but I believe it is only effective supporting their sales pitch "No more filters to buy".  I do not believe you would be able to wash the smallest particles out of the filter pores.  It would allow it to let air through "better" but not as good as a new filter.

Power nozzle almost the same as the SE "Performance" just there is a thumb wheel that allows you to lower or raise the nozzle to adjust it to thickness of the carpet.

Electric hose - no more "Pig tails"!!!  Power gets connected as you plug in the hose (Power supply and hose connector are in one piece).  So this makes the hose much more durable - thank you Rexair, Inc.

Overall - if you can deal with the higher price - go for it.

Power unit looks just the same as a regular SE.  Inside motor has a bit wider carbon brushes.

Electric hose has a trigger on the handle that allows you to turn the power nozzle ON or OFF without turning off the vacuum itself so you can stop the brush roll from spinning and vacuum bare floors with the carpet nozzle.

The nozzle itself is really different.  Totally new design.  Does this nozzle work better than prior design?  Lets trust the manufacturer and assume that they have done that research.

This nozzle is a bit more fragile though, so be careful - do not step on it or let your children dance on it while you are vacuuming :-)

Same power unit and same carpet nozzle motor.  A few cosmetic differences (color, dolly, nozzle).  Better plastic used for top portion of the main unit.  This plastic is easier to remove scratches from so you may expect remanufactured units to be much better looking than prior models

Electric hose with pistol-grip handle is introduced.  Power nozzle has a short cord that is plugged into the hose (on the handle). This makes it very easy to switch from vacuuming rugs to above floor dusting and back.  Regular "wet" hose is still included.  DO NOT vacuum water with electric hose - DANGER of electric shock!!!  Electric hose has a short "pig tail" that gets plugged into the power unit.  This "Pig Tail" can be replaced only if you replace entire hose and the hose is VERY expensive (close to $100 USD).  So please be gentle and unplug the hose holding the "tail" by the plug.  Do not just yank it out.

After the D3 model this one was the fist one to have a newer power unit motor (main motor) than had been used in Rainbow vacuums for almost a decade.  Because this motor was out there for such a long time and so many of them were made, getting a remanufactured motor is relatively cheap.

The power nozzle is the same as D3 just a bit darker shade of brown.  The long cord is still strapped outside one of 2 regular wet hoses and runs all the way up where it is plugged into the main unit.

After the Rainbow D2 vacuum model, this one was the first one to be all plastic.  Rexair, Inc. was experimenting with motors so you will find 2 different kinds of them in D3.  I personally like the design because the motor is quieter than later models.  But they are really hard to work on and parts are very expensive.

The power nozzle (piece for vacuuming rugs) has a long cord that runs outside of the hose and is strapped to it with 6 straps.  This makes it a bit inconvenient going from carpet vacuuming to bare floor or above floor dusting.  To use the attachments you have to change to another hose (supplied).  It is a hassle but still much faster than taking the straps of and completely disconnecting the nozzle.