I would like to know your opinion about webs that offers to buy houses for cash.

seems the assumed returns on syndicated deals could get crushed.you are correct to worry about this. that is why you need to look at sponsor assumptions and see if they stress test their projections. most will publish a 3 part scenario (good economy, stagnant economy, poor economy) and some will have a whole range of projections (sometimes you have to ask). and yes, if interest rates rise a ton, some deals will get crushed, that is why part of your due diligence is to study the terms of the loans and see if you are comfortable with them.

Are there any published or known numbers for what constitutes a "good" return on an investment?

Even though the Richest Man in Babylon was published way back in 1926, the lessons are timeless.

All of the large advisors/brokerages publish cap rates on their websites for free. 

These [This] district should be located only where all necessary public utilities are available and where transportation systems are adequate.Uses permitted by right:Aquaculture.Automobile assembling, disassembling, painting, upholstering, repairing, rebuilding, reconditioning, body and fender work, truck repairing or overhauling, tire retreading or battery manufacture.Building materials sales and service yards.Commercial kennels.Contractors equipment and storage yards.Convenience center.Convenience store.Data and computer services centers.Fleet parking.Flex office.General office uses.Hotel.Laboratory, research and testing.Light industrial uses.Light manufacturing uses.Machinery sales and service.Microbrewery in accordance with subsection 28-39(w).Motor vehicle rental.Parking and storage of tractor trailers.Printing, publishing, engraving.Public facilities/utilities but not including propane and heating fuel distribution facilities, generating facilities, substations, switching stations and wastewater treatment facilities which are permitted as a conditional use permit.Public parking lot.Public works excluding wastewater treatment facilities.Railroad sidings.Restaurants without drive-through.School, vocational.Selected indoor recreational enterprises within industrial parks.Storage warehouse.Veterinary clinic.Vocational school.Warehousing, mini-storage.Welding or machine shops (including the use of punch presses not to exceed fifty (50) tons rated capacity).Wholesale business.Conditional use permit:Adult business.Airport, private.Boat sales.Brewery.Clinic, medical and dental.Communication facility.Distillery.Drive-through.Dwelling for watchman or caretaker on-premises.Low intensity commercial retail not otherwise listed.Medium intensity commercial retail not otherwise listed.Microbrewery, in accordance with subsection 28-39(w), with facilities for events such as weddings, parties, and/or events with two hundred (200) or more attendees.Motor vehicle sales.Other light industrial and manufacturing uses not otherwise listed for this district.Place of worship.Public facilities/utilities for propane and heating fuel distribution facilities, generating facilities, substations, switching stations and wastewater treatment facilities (except for the expansion or modification to a wastewater treatment facilities existing prior to October 17, 2006).Recycling facilities.School.School, industrial.Truck stop.Vehicle fuel sales.Here are some questions I have:1.

As I am expanding my business, I am looking for help building a website, building SEO, and getting help from someone who is great at marketing. If they have experience in the real estate industry that is even better!T...

However, I also have seen published articles that reflect comments from office workers complaining about the concept, and the inability to get work done due to interruptions, noise, etc.  

Nope, I'm not a scientist, but I am fairly certain no good news will ever be published about living under power lines. 

Even with all the reviews and testimonials available on the web, looking people in the eye is still the best way to gut-check your decisions.