How do SVS subwoofers compare to REL?


I'm looking for subwoofers (one or two) that have a very "tight" natural sound and are not overly boomy. In the future I hope to pair them with some Magnepan speakers. Magnepans are known for having a natural sound, and I want to compliment that.

I've been told that the REL subwoofers (e.g.,T/9i or S/3 SHO, etc., are a good match for Magnepan speakers. However, SVS subwoofers have also been recommended to me.

I don't have any background in high-end audio, so I am interested in opinions of folks here. Are SVS subwoofers considered generally as good as REL in regard to the features I'm interested in? Is either clearly superior? (I had never heard of SVS before yesterday.)

Which subwoofer size (in REL or SVS) would be a good match for a pair of Magnepan 1.7i in an 18 foot x 15 foot room (ceiling about 10 feet) with carpet on floor?

I'm looking at these so far:

REL T/9i Subwoofer about $1300
REL Acoustics S/3 SHO Subwoofer (Super High Output) about $2100
SVS SB-4000 13.5" 1200W about $1600
Any other recommendations?

Total subwoofer budget is around $2600 max. ($2000 or less would be better.)

Also, I believe it is better to buy two smaller subwoofers, compared to one larger one, right? (I'm just not sure where I would put two. Placing one is easier in this room. And I plan to connect everything with speaker wires, not wireless.)

Thanks

lowoverdrive
I recently purchased the new bowers and Wilkins DB3D sub. it is one of the most musical sub I have ever heard. It is fast and iron fisted tight.( 2 opposed 8” woofer with a 1K amp. It is absolutely seamless with my speakers. I know it wont get much love here as it is expensive. There are endless software adjustments with this sub. I believe its almost impossible not to get seamless integration with any speaker. 
I'm not yet ready to buy used equipment. I don't know enough. I'm going to buy new so I can return the item if I make a buying mistake.
Taint thunder you are hearing, its one ( or two) of Richard's subs! RIP
For me, REL over SVS.
Another purchasing tip are the REL Q108 IIs on Ebay for around 300 bucks or so. That model shows up frequently and I found one a few years ago for 200 bucks, but I was lucky. For a single 8" 100 watt design these things are amazing.