What is the forums opinion of SVS subs?

They’re largely different designs. Yes, on paper SVS will deliver more deep bass per $ and sound quite good doing it properly set up, which is now much easier with their Pro series that includes integration software. Rel prefers to run off the speaker-level output and doesn’t offer integration software but by nature is easier to integrate without it. Bottom line, I’d take two sealed SVS SB1000 Pro subs at $1150 over one Rel sub because there’s a significant benefit to having two subs versus one if it comes to that. Past $1150, well, it’s all about budget. Don’t think you can go wrong with Rel, but then you start getting into Rhythmic, JL Labs, etc. territory that muddies the waters. Then it becomes a decision if using a speaker-level input or line-level input with integration shortware is preferable. Me? I’d read reviews of the various options and go with the one that offers the most of what you’re looking for. I don’t think you can go wrong with any of the above brands, but I will reiterate though that using at least two good subs is much better than using on great one. FWIW.

I have a micro 3000 and a PB2000, I enjoy them both. I have heard the REL is more musical, and I can’t confirm or deny that. But for me the SVS subs are just right for my needs. The adjustability via the app is awesome. Very versatile and lets one really dial things in. Also a plus, the SVS are priced right for me. You get a lot for your dough.

I never owned REL. I have one SVS  purchased to add to the existing two HSUs already in the system. If the HSUs ever fail I would definitely go for SVS as replacements.I love that app.Adjusting all of the settings from my listening chair is great.

YouTuber Nemo Propaganda does a good job of doing explaining the differences between the two brands. Might want to check him out. I too had a hard time with REL’s specs as on paper they don’t seem impressive. It’s hard to explain, you kind of have to hear one. They produce bass and have extension but it’s like there is no sub in the room. Just more low end articulation that seems part of the mains. The two brands are just different philosophies. No right or wrong, it comes down to one’s preference.

I own one of each, a REL S2 and SVS SB1000 Pro, and I prefer the SVS. They augment a pair of OB speakers in a 16' x 21' room to great effect where you feel immersed in the sound.

As @soix mentioned, 2 subs better than 1.  Easier to get good sound.  3 subs even better!  Multi-subs are able to smooth the lumpy bass found in all rooms.

A while back I managed to borrow 2 ported subs to play with and found them a little difficult to place and that is why I chose the SVS sealed unit. I placed the SVS in the rear right corner and the REL about middle of left wall. Omnimic confirmed a better room response than the 2 ported designs and that was before any fussing over their positions.

The SVS has continuously variable phase adjustment and with the ability to change settings from the listening seat is a great help. In addition to phase there is also low pass, parametric EQ, room gain compensation and presets.

The REL ( it's the S2 I think) which I found used at a bargain price was placed along the side wall so I would have the option of moving it about for best integration because the phase is only switchable from 0 to 180 degrees.

Setting up these 2 was a breeze. With Omnimic guiding me I moved the REL backwards and forwards, each time readjusting the SVS then move REL again and further tweak the SVS and so on. Will now build myself a servo-sub to add to the fun.