The Forint has experienced some serious changes in the last months. Earlier this year one Euro could be bought for 230 Euros, but in these days the value has changed to approximately 280 Euros. The dollar, which earlier could be bought for around 150 forints, can now be bought for 200 forints.
Because of this, your money (Euro, Dollar) as a tourist will be more worth in Budapest in these days. For how long the Forint will be as weak as now is not possible to tell.
Even though it is so, some changing shops are still charging a lot as you change your money, so be sure to check that the difference between what they are selling and buying your currency for is not to big. For example: It they sell Euro for 285 Forints, they should sell Forints for 270 Forints. If the difference is like this, it is okay, but if it is bigger, you should look for another place. If you are lucky, you will find better places as well!