Staining to match wood has been successful.
Spray painting with 'Krylon' brand paint is moderately successful. It had a better bond than other brands I tried, but was subject to damage from contact with any hard surface, including pipe clamps, tools, kids toys, etc. Can scratch it off with a fingernail. Above routine contact height it has lasted 2+ years so far.

Stains are designed to soak into porous surfaces. Paints leave a film o the surface. Primers are designed specifically to bond and adhere as well as block stains/lettering, etc. Primer + topcoat is better than two coats of paint. Most acrylic latex paints bond well to plastic, to the point where I don't bother with primer.
My suggestion is to check with your local paint store, as there are many new products and technologies, including paint and primer in one, paints designed specifically for plastics, and various epoxies.
Based on my 20 years of mitigation and 12 years in the remodeling business, I will say that spray paint does not hold up well over time, and that a good bonding primer and acrylic latex topcoat is the best way to go.
FYI, there are small, curved paint rollers available that are made for painting round pipe.

A nice thing about the pipe color matching the building color is that the pipe can be painted in place after installation.

I agree with Henri. My only caution is to be careful about painting the pipe sections before assembling the pipe. The thickness of the paint will interfere with attaching the pipe to fittings. We learned this the hard way!

We have had success with Krylon Fusion (made for plastics). I strongly agree with Dick that painting the piping after installation is best. Any paint on on the solvent glue surfaces will hamper the assembly of the vent. Painting the piping several months after installation allows the suns UV rays to break down the oils used in the manufacturing process of the pipe, fittings and rubber couplings. Make sure if you paint the fan to protect the fans label for the purpose of later fan identification and/or warranty claim.

Thank you!

Thank you!

Thank you

Yes, Dick. We usually assemble and install the vent pipe, then take it down, paint it, and reinstall it. This can be problematic with a tall vent pipe. One can also wrap 1 1/2" masking tape around the pipe ends when painting them so there is unpainted pipe to cement into the couplings.

We have used the masking tape technique. Sometimes we'll have to do a little touchup at the joints after the pipe is re-installed. And, yes, tall vent pipes can be challenging.