I switched from Superb II Eleg with rear side and tailgate blinds and sunset glass fitted as extras, amongst a few other bits. I paid £21k for my spec Octy III and for £1k more I could have had a late pre-facelift 170CR Superb Eleg with Park Assist, Ventilated Leather, Heated Screen and the rear blinds. After 4 years with the Superb I was ready for a change and didn't expect to get the FL Superb for the same deal if I waited, so nearly went for a Mondeo, but the £3k saving off list on the Octy III on launch weekend tempted me into signing. On the whole, having driven 5k so far in the Octy, I would summarise as follows:
Space
Not an issue, the new Octy is as wide as the Superb so you can get two child seats in the back, side and middle and a small adult on the other side, bit of a squeeze but no worse than in the Superb, the loss of about 3" of rear leg room does not matter, there is plenty of knee room for two tall adults to sit one behind the other. In the Superb, I often found it a pain that I could not reach across to one of the kids without undoing my seat belt, when stationary of course! Boot space comparable to Superb also. The Octy is also easier to park as it is 150mm shorter overall so fits better into regular parking bays.
Toys
Swings and roundabouts really, the new audio and info computers in Octy III are streets ahead of old tech in Superb and it seems FL Superb still on old kit. I don't miss the leather as I used to overheat on long journeys, even without the seat heating on and even in winter. Not had any issues with the Alcantara in this summers heat wave. Apart from the blinds and sunset, not really missing anything, thinking about getting the rears tinted though on Octy.
Engine
Comparable power to weight ratio between Superb 170CR and Octy 150CR, if anything, the Octy is quicker, especially in sport mode, economy loads better also, not as good as official figures would lead to believe but I am getting similar range of about 500 miles and saving at least £10 per fill up due to smaller tank which equates to about 15-20% saving, big saving on road tax too.
Styling
Octy has better side and rear styling, feels more in proportion, Superb is just too big and the twin-door makes for a bit of an ugly rear end, I am not comparing with the Combi as I have the hatch and had a twin-door Superb. The FL Superb does have better rear lights but the side profile still not as handsome as Octy imo. Superb II pre-FL front end is still awesome imo, I do like the OctyIII front end too, much better than Octy II FL, but now that they are all going to look the same, I would rather each model retain some individuality.
Build Quality
I hate to say it but this is the one area where the Octy III is a little disappointing. I have a few squeaks and rattles, one was so annoying, I had to return to dealer and it was cured, but there are a few others now, not major issue, whereas the Superb just felt more bomb proof and only just started to creak on the drivers door after 80k. Octy is still a nice place to sit and the driving position is better for me than in the Superb as the seats feel more comfortable and the centre console does not intrude as much as in the Superb, I used to get a sore left leg due to it rubbing on the edge of the console on long journeys. Most of the bits you touch in the Octy are nice soft touch, some of the plastics in the centre console and lower down are a bit hard, but that is no worse than the Superb or other models from other manufacturers. The biggest disappointment is the door cards, the Superb had soft touch tops, similar to Octy II. I think they were trying to prevent the delaminating problem that my Superb drivers side door card suffered but I would rather have a softer resting place for my elbow and put up with a couple of bubbles in the plastic!
Overall, I am happy with the change, I think anyone upsizing or switching from Octy II will find the Octy III perfectly adequate. Ex Superb owners may have mixed emotions from time to time. If they sort the styling on the Superb III, and slot in a 150CR with the new audio tech, I will probably be first in the queue but for now I am glad I switched and will enjoy my time with the Octy, after all, it's only a tin can on wheels!