No big deal. Some of the largest UK property companies like Land Securities and British Land (they buy, build, manage, rent out and sell offices, industrial estates, DIY sheds etc) converted to REIT status a few years ago because there seemed to be an advantage in the tax treatment.
Since then, commercial property values took a big dip; some property companies went bust, or nearly; and the remaining ones will probably not be converting to REITs because they currently don't see a tax advantage in doing it.
There's nothing wrong with having shares in a REIT as part of your investment portfolio, if you're a person who has an investment portfolio.
It would be unwise to put all your money into commercial property, because you might suffer another enormous drop in value. You would be deluded if you thought you could forecast which would be the big, safe, dependable companies that won't crash (BT, Barclays, Railtrack, Land Securities, Rover, BP?) If you want to research it, I recommend you go to your local library and ask to see their back-issues of Investors Chronicle (a weekly magazine, full of hard-nosed information and advice aimed at the private investor. It doesn't try to sell you anything and has no axe to grind). They do have a website, but the up-to-date articles are subscription-only.
Beware of taking advice from anyone whose next Jag will be paid for by commission.