I've got myself an ARS90S 4U. Only had one session with it so far but pretty impressed. Got the timing straight away. Will post again when I have had a couple more sessions.
After a few more sessions with this racket I can say that I like it a lot.
I have been using a JS12M 3U for a while and was in two minds about getting the ARS90S in 4U but in the end decided to go for it to see if could match up without sacrificing much power.
Tale of the tape comparision:
JS12M 3U 97.0g weight 290mm BP 40.9g head weight
ARS90S 4U 89.5g weight 300mm BP 39.1g head weight
Both rackets strung with Ashaway 66 Fire Power and an over grip on top of the factory grip.
ARS90 head is slightly larger than JS12. Both rackets are the same overall length so the shaft of the ARS90 is a few mm shorter than the JS12. The ARS90 does feel a tad stiffer than the JS12.
The frame does have more 'sword' edges then the JS12 as well as thinner profile at 3, 9 and 12 o'clock.
The ARS90 is quick and manoeuverable as you would expect. I am not a natural net player but the ARS90 made this aspect of the game a lot easier for me. I also found it easier to play deceptive shots by delaying shots.
When defending, the ARS90 did at first require a bit more effort to play block returns than my JS12 but once adjusted to the lower racket weight this was resolved.
The sweet spot is easy to find and when connecting a smash properly plenty of power can be generated.
One aspect I really enjoy is how easy it is to do good steep stick smashes.
No issues with getting good length on clears or defensive lifts.
In summary IMHO this is a vey good doubles racket!