Can't wait to go back
I visited a couple years ago and loved the place. I stayed at the Hotel Del Rey my first two nights there and the remainder of my stay at the Hotel Presidente, which I found to be much nicer, and it's just around the corner. And the Presidente doesn't charge you to bring "guests" to your room. The Del Rey does, or at least it did then. Breakfast is even complimentary at the Presidente. Then again, if you are a single guy traveling to San Jose with a couple buddies, my guess is you aren't going there for the food. Traveling on foot is fine during the day, but at night I would certainly recommend taking a taxi, especially if you have a Tica with you. There are a few other spots in town to get some action - the taxi drivers and locals can tell you where - but the Del Rey is really all you will need. It was relatively quiet during the day, but around 9-10 PM the place starts rocking. You will feel like a kid in a candy store. Most of the girls speak decent English, but knowing some Spanish will certainly help - not just in the Del Rey, but in San Jose. Security is pretty good at the hotel. Gringos can come and go as we please. Once you set foot out the door, however, expect to be hassled. Locals will try to sell you cigars and fake Rolexes and flowers for the Tica on your arm. Kids will bombard you and beg for money. As with traveling anywhere, be smart. Leave your passport and valuables in the safe in your room. And don't wear too much bling.
San Jose is a decent place to hang out. I spent some time in Quepos and, while the scenery and beaches are okay, I felt like I was constantly being ripped off. I went to a night club, where they were trying to charge me $12-$15 per drink. The girls I was with were ordering cocktails, which turned out to be nothing but soda, and the bartenders were giving them chips (to cash in later). They would not leave the club with me, either. The club had guest rooms, which they were asking around $200 an hour for. I guess the girls were employed by the club to take advantage of unsuspecting Gringos with deep (or not so deep) pockets.
Stay in San Jose. Stay at the Del Rey or Presidente. There is even a Holiday Inn there, which you don't have to book as much in advance. You will have a blast, and once you get back to the States, you will already be planning your next trip.
Another tip: Most places accept USD, but will give change back in Colones. Always do the math and make sure you are receiving the correct amount of change.