Ok, a few basic facts for people who would like to invest in commercial space in Dubai. First of all, know the difference between freezone and freehold properties.
JLT, Tecom and DSO are freezones. This means that the clients that you can lease your office space is restricted to certain requirements. For eg:
1) JLT - Companies only in the metals and commodities business can set up office here. You cannot give your office space to a software company, a medical center or any other kind of business.
2) Tecom - Only for Telecommunications, E-commerce and Media companies.
3) DSO - Only for companies in the silicon industry (semiconductor) business.
Freehold office spaces are where there is no restriction as to who you would like to lease out the office space to. Currently, there are very few freehold office space areas in Dubai, most notably however are Business Bay, The Onyx and Escan tower. You can lease it to anyone and no one can question you about it.
Please consider these things when investing as companies in freezones are supposed to take permissions and conform to the rules of the respective freezone governing entity.
I don't mean to rain on anyone's parade but i don't like seeing people being scammed. There are a few towers in JLT that are currently very SLOW in construction such as HDS Business tower, Jumeirah Business Centre, Mazaya Business avenue. I have done enough research on all these areas and hence know what the current market value is. You can easily find office spaces for as cheap as 1350/Sft in all these 3 projects as they are pretty much still at the base level. If you have the money and would like to see capital appreciation over time, these are good options as you don't have to pay much right now. However, if you want immediate rental income so as to capitalize on the current market demand, please try to invest in towers that have completed or are close to completion.
Another tip is to try and invest in office space close to the metro station. There are just about 10 towers within minutes walking distance to the metro stations, so it shouldn't be too hard to decide which one's to pick in!
Good luck with your investments guys.