I like it.. what didn't you like about the site?
@JTW Don't get me wrong I love the Aimpoint and I don't thing you can get a more robust red dot - I will probably move it to an AR. Having it on the MPX and shooing it is some of the USPSA match I found that there is just enough of the case surrounding the glass that it obscures some of your close in vision - that has caused me to miss seeing some small steel tagets. - I have tried to get the Aimpoint out a little farther on the rail to see if that helps but it still happens.
I have an old Burris Fast fire that I am going to test out - I have not shot in a match but mounting it last night I can tell that it does not obscure anything. If I like it on there I will look to replace it with a more robust RMR down the road.
I originally bought the MPX because I have always wanted an MP5 (but never say myself spending the cash for a real one) and the MPX came out. I love this little gun. 8" barrel that I eventually want to replace with a 4.5" barrel and suppressor under the handguard.. in theory it is a perfect house gun at that point. I have a suppressor now and it is pretty darn quiet when you shoot it.
Never had a Sig before and they hit it out of the park with this model - they just need to fulfill some of the promises made in the beginning like offering different barrel lengths to swap out and the caliber conversions.