Is it better to pray at home or at the mosque?

I work in Saudi Arabia and go back home after every one year. I belong to Nainital district of U.P. (Now Uttarakhand) which is very near to Bareilly and the Barelwi Maslak is rampant in that area. “Mazar parasti” and Urs, etc., are the foremost part of their Islam and Aqeeda. In my village there are only two mosques and the Imams leading the prayers are staunch Barelwi. I had a discussion with one of these Imams of our moque, he has the belief that to ask for help (Mannat) with the dead (Mazar) is as good as praying God. Since then, I stopped praying with him. I offer all my five prayers in my home during my vacation of one month or so. Secondly, my wife is very punctual in prayers and other Shariah matters. She also joins my prayers which I lead in my house. Please enlighten me on;(1)if, under the circumstances explained above, my prayers in my home are correct, (2) prayers led by me and joined by my wife are correct. or I should go the mosque and pray behing the same Imam as explained above. I shall highly appreciate your immediate reply on the above e-mail address. Best regards