With Metal it is good to have a very fast 'hard gate' feature. A hard gate instantly clips your total signal clean off. It is stunning for 'STOPS'. The Metal buzz word for rests in the music. So even if you feel you do not need one for noise the 'hard gate' affect is hard to resist.
The NS-2 has been around for 10 years and has been the go to pedal for most Metal players.
Many owners also claim it does not affect your tone. After many listens
I think it does. It fattens it up. :-)
I already have 2 TC Electronic Sentry's 2 OD loops coming from my Boss Switcher. One for low and medium gain OD's and another for high gain OD's They are bit harder to set up but have a lot of fineness.
A better choice if you are more into low or medium gain pedals and you want to sanitize a lot of hiss and a bit of noise.
I use the Boss for my Fuzz and Metal pedals and works beautifully.
I had a single end Decimator but it was really hard to get a sweet spot.
Different pedals needed the gate changed and it caused embarrassing delays between songs at gigs getting it set right.
The price is quite reasonable if you are going 'new' but
they can go as cheap as $35.00 USD for a beat up job used.
I bought mine used in excellent condition for $62.00 USD.
I feel it was the best compromise as a beat up jobbie may have electrical problems.