If memory serves me, there is no lounge to use at PBI. The BA lounge at FRA is by the BA gates at the very end of T2, and it requires passing through a second security barrier. I don't know if there are any other oneworld lounges in T2, so you may be in for a pretty long walk back to your gate. And unless you are departing at a heavy travel time which coincides with international flights served by CX, AA and other long haul oneworld carriers, it is unlikely their lounges, if they exist, would be open.
The BA one has smoking and non-smoking rooms, though when I was using it a few weeks ago, nobody was enforcing the non-smoking rules in the non-smoking room. [It is actually operated for BA, though it has all the decore and trappings of an ExecClub, just no BA agents at the reception desk.
As noted, the BCN lounge is rather bland and utilitarian. Also, when I did BCN-PBI, the gate numbering proved very confusing so once you get to the proper pier, be sure to confirm where your gate is.
Finally, rest assured, IB's European and domestic service is much, much better than its international, even in the bak cabin. The seat pitch is a couple of inches more, and the FAs actually smile instead of scowl, and come to your seat to serve you, rather than you having to go to the galley to get drinks, once the meal has been served.
[This message has been edited by Shareholder (edited 07-28-2002).]