It depends.
The previous posters highlighted some of the negatives. In addition:
1) Financing is usually worse in terms of rates
2) HOAs can and will go up over time. They also make decisions good/bad for your investment so it depends on their interest (less rentals for a more owner occupied, paint the exterior, maintenance, etc.)
The positives of condos are:
1) You can get in for a lower price than SFH in certain areas
2) HOA is a deduction as a rental
3) Condos in general require less management from me. I need to focus on interior management vs exterior which is good for self management but not as cost effective
4) They offer some amenities with those HOAs that are divided up that might increase your rent (pool, fitness center, club house, etc.) and some tenants are looking for.
It really depends on your market. This is just an example but I bought a 1/1 condo in 2010 for $150k with 30% down that cash-flowed $300/mo immediately. That condo got me another rental property for what I could afford at the time. I was able to 1031 it into a 3/2 which is now $580k. If you see a good opportunity for a condo and the numbers work (don't bank on appreciation), then i would say go for it if it gets you into the market. At this point though you can also find deals on SFH that cashflow great but might not be in appreciating areas.
Collin