Both cabs are killer if you like Vintage 30s like I do. My vote goes for the Stiletto 4x12. I made multiple visits to the nearest mesa dealer with my MK V before I decided to fork over cash just to make sure my ears liked the same cab on different days and moods. I even tried out the Road King 4x12. I was really wanting to like that one for the open back versatility but I just didn't connect with it at all.
The Recto 4x12 has alot of bass and sounds mid scooped in a way I guess. I have heard people call it the cabinet of mud, but I didn't think so with the MK V. The MKV is a tight amp with lots of midrange and you can dial out most of the bass with EQ. I thought it sounded great and I can see why so many people use it. It also sounds big.
The Stiletto 4x12 suited me better because I like the tightness and midrange evident in the cab. I thought it made my music sound better combined with the MK V..... Its sounds great chugging palm muted chords and sings when your playing leads. I love it. It just suits my playing style and the tone I hear in my head more than the Recto 4x12 did. Oh I got the straight version. It is more directional than the slant, but it just sounds better to me.
Mesa makes killer sounding cabs. Let your ears decided which one you like the best.