I I am however fond of letting notes decay into feedback like at the end of a solo or whenever the feeling is right so i was wondering what you would recommend.
You will not get ANY noise reduction pedal/system that allows you to do this. A lot of high gain folks just use their NR pedals for rhythm playing and then kick it off for solos. Getting a NR system to work well for solos is almost impossible.
The Decimator is as good as anything out there, but NR pedals are not a wonder-cure for a noisy rig. Also consider a way to get the tone you want without the noise in the first place. Maybe a different EQ. I assume you are using a "smile" curve. You could try a very high quality parametric EQ pedal to do the same thing - something like
http://www.catalinbread.com/Varioboost.html .
I've been down this whole path, and in the end I decided I couldn't live with the noise. Something like an ISP Decimator is only actually a noise gate, either fully open or fully shut. When it's open, when you are playing, you still get all the noise over the top of your tone - I couldn't live with that.
I'm lucky I'm not a particularly high gain player - I know it can be a nightmare. if you are going to persevere with noise reduction, then it is better to use a "little" NR at various places in your signal path (eg, before the amp, and also in the FX loop), rather than one big load of NR at one point. Something like -
http://www.isptechnologies.com/decimatorprorackG.htm is about the best you can get.
Having said all that, I'm sure that you are probably constrained by a budget. You may as well get an ISP Decimator and try it out, it might be enough NR, when set reasonably low, to fit your need. You can then switch it off when you want to let notes decay off into feedback. I'd say it would be a good idea to buy it online from somewhere that gives you a clear 7 day return option for a full refund. if you are in the UK, then there are loads of retailers that offer this.
Alan