the thread clubber links to above says all you need to know really. youngs modulus says 2 frames of same dims but different steels will feel the same but strength will vary and the basics of tube section / wall thickness are what affects frame 'feel' the most. for 'feel', you can usually substitute 'level of flex'
OP – even basic cr-mo is known for it's durability, so i'd say buy a steel bike based on tube dims and geometry, not the tube brand (unless Reynold's UK made tubes give you an irrational good feeling, they do for me). the higher spec tubes could be made lighter and flexier for a given strength and there's certainly a big difference in comfort/flex/tracking ability (all aspects of the same thing imo – tube stiffness levels) between a frame with a 31.8 DT and 28.6 TT and another with 34.9 DT and TT.
the Altitude has approx 68.5-68.75 degree static HA with a 120mm forks on it. whether that's 'slack' or not i'm not sure these days, feels good for general trail riding though and it's less twitchy than many bikes (..similar to most good 'UK designed' bikes then).