I have a small position in a 5.5% PR General Obligation. It started off being a pretty sizable position in 200 but as interest rates dropped, the bonds have been gradually redeemed.
Brewer warned me and others a couple of years ago about the terrible condition of PR finances. I put it on my to do list to sell it and never got around to it.
Last fall I tried to sell. It turns out the price Schwab's computer say the bonds are worth $950 is quite a bit higher than human is actually willing to pay say $880. The bonds mature in 3 years so with a yield to maturity of 9% I'm going to bury my head in the sand and hope for the best. I figure my break even point is getting more than $.75 on the dollar in bankruptcy. But if they can kick the bankruptcy down the road for 3 more years I am home free.
I figure worse case I'll have a seat at the largest muni bankruptcy. Plus since the bonds are insured by the AMBAC who's financial condition is as bad as PR. I figure I'll also become a creditor of AMBAC and will get twice as much legal paperwork to read
Unless you've got some expertise in the field, I'd personally stay far away.