I did it on my own dime a couple of years ago, wound up costing about 4k total.
Was it worth it? Depends on how you look at it.
From a purely financial standpoint it took probably 18 months to get that 4k back through instructing. The school I do some work for has several, but they just don't fly that much. I only got one or two calls from individual Cirrus owners for recurrent training and there are a lot of the airplanes here in Minnesota.
The whole Cirrus thing, at least here in Minnesota, is kind of weird. Even the really experienced CSIPs just aren't getting a ton of business from individual owners. We've talked about it among ourselves and either we're just horrible at marketing or folks just aren't doing a whole lot of recurrent training.
I think the insurance requirements have relaxed a bit. Most policies used to require recurrent training but I get the feeling that's not as common. A surprising amount of owners seem to be willing to pay much higher premiums and just fly the things without an instrument rating and, I'm assuming, nothing more than a flight review for recurrent training.
In hindsight, at the time it would have made more sense to take that 4 grand and spend it getting my MEI instead. Oh well.
The real benefit, for me at least, was getting to take some great trips, having a lot of fun and making some very good contacts.
One of my Cirrus clients recently bought a 340 and I'll probably do some flying in it for him. Another is chief pilot on a G200 and with a little luck I might wind up working for him eventually when they have a seat open up. Another has a position on a Cirrus jet, so who knows where that may lead.
Even if I don't wind up working for any of those guys they know me, like me and I'm sure they'd toss my name out if they heard of a good opportunity. So, from a networking standpoint it's been a good thing.
It's a fun airplane to fly and teach, certainly a nice break from a steady diet of 172s/Warriors but I'd doubt going through the CSIP deal is going to open up a ton of new flying unless you're already working somewhere that's flying the wheels off of a few Cirrus. Hopefully I'm wrong about it though.