I had heard of sani-flo and all the different products to solve problems with non-sloping drains are very tough to slope to a drain. In this case a slab issue caused the kitchen sink drain to become unusable. It was to go outside and dig and install a 2" pvc line and cut and break up the concrete driveway and then go about 60' to to the 4" line in the back yard. I decided it was less cost and quicker to purchase the SaniiFlo and install it. I ordered this from Amazon at a good price and a few days out. Very acceptable. It arrived and I started to install it.
1. a nice small footprint for under the sink and I set flush to the left side.
2. is to connect existing sink drain to the correct top outlet. this was the quickest and easiest part
3. then I connected to the existing vent stack. (this is must or run a new vent stack.)(automatic vents not allowed)
4. lastly I ran 1" PVC as the new drain line out the wall and up on the outside of the house and then into the attic. I ran maybe 35' to a 2" cast iron vent stack, drilled a hole and inserted the 1" pipe and then sealed with Dow silicone caulk,
Plugged the unit and off to the races. Very quiet and quick pumping.
I would recommend this as an option.
Note: This unit was the smallest one I wanted to try but it was way under utilized as it can have had more fixtures dump into it and still work great. This one was for grey water only.

I like that it was easy to install and that I did not have to cut into my walls to install it.

The pump itself seems to be reasonably well built and works just fine for a basement utility sink. The only downside is that none of the advertised parts were included (and the box it came in was not even large enough to include the parts). Minus one star for the missing parts.

On a positive note, the second top inlet can serve double duty to connect a combination air vent and overflow drain. You just need to cut a hole for whatever fitting you use to connect the vent/overflow line to the side wall of the sink.

Nice compact unit. I wish its capacity were a bit larger, so it didn't have to cycle so often when doing laundry, but the bigger ones I found wouldn't have fit under the legs of the laundry sink. I needed one more connection to a 1.5 inch line than what was provided. I registered the product (I hope), but the serial number location given as an example on the SFA website did not match the one on my unit. Time will tell how long it will last.

Not silent, but quiet, am using it for a shower and sink. It shoots up nearly 8' before entering the house plumbing. Goes on and off regularly during a shower or sink wash. It does not stay on. I ran mine on it's own 15 amp power line from a satellite breaker, if running with lights, it may cause dimming during operation.