I fly IAH-GIG quite frequently and find that the service is decent (depends on the FAs). For me at least, there is very good upgrade success. Having said that, I personally would not spend $500 plus 25k. My threshold is about $350 for this route. The miles are immaterial, imo. If it was a lower co-pay I'd say definitely jump on it.
These days $500 can go a long way in Brazil with the exchange rate ^