According to Hitchcock/Truffaut Interview, Hitchcock told Truffaut that he considers The Lodger as his first true film.
As for me, I thought The Lodger was a brilliant film. Hitchcock's original ending wasn't used, because Ivor Novello was a big star at that time.
So a happy ending was used instead. But Hitchcock implied throughout the film that the lodger might be Jack the Ripper.
Although there is a happy ending shown in the film, still it is an open ending. You can pick your choice. Is he the avenger or not? There isn't a single evidence to prove that the lodger's story about his past and his sister is true. So it is upto the audience to pick the choice.
Hitchcock's camera shots are brilliant especially the scene where Ivor Novello is walking and chandelier is shaking. No. 13 is common in Hitchcock films. No. 13 is house no. where Daisy lives. We see the no. 13 on the front door when Ivor Novello's character knocks on the door in the beginning.
In Shadow of A Doubt, we see Joseph Cotten's character coming out of No. 13 door.
In Psycho, we see Car No. "NFB 418." NFB stands for Norman Francis Bates. Add the numbers - 4 + 1 + 8 = 13.
As for me, I liked it. The version I saw was brilliant. It is the black and white version released by St. Clair Vision in 2005. I didn't like Video/Film Express Version. But that's just my opinion.
I recommend this film for any Hitchcock admirers.