This is what I did when I bought my first place in Spain. I rented a car and for the 7 days did nothing but drove around and went to all the developments.
On my 2nd trip, I bought a place. In those days it was very difficult to keep an eye on the market as new development/sales offices were springing up every six months.
By all means go with the Agents use their services, market knowledge, sit back and give yourself time and than go out and you may get a discount if you play hard.
No, shame in missusing an agent, they are not reincarnation of mother Teressa.