from the feature set I wouldn't use the Express one. Mostly this solution have enough features, but you can't extend it. The Instant APs have maybe comparable features, but you can extend it with AirWave or a controller and a firmware update. This is with the Express not possible.
Hi, Captive portal is very powerful compared to Aruba. Remote debug functions are very powerful with the WiNG and not possible with Aruba. This are the two best functions compared to aruba. The VC from Aruba Instant is better at the time. I wasn't use the VC from WiNG, use a VX9000. For configuration WiNG provide more options, if you know what you'll do. Aruba and a lot other vendors are limited in the options. Best regards Timo