I tow a 5er with a short bed. It is easy to do and well within my comfort zone.
If and when I trade my '01 F350 in, I will probably get a long bed, but I am not in any hurry to do it. I might continue with my SB for years.
I personally would be more inclined to examine the pin weight of a loaded Alfa with respect to the TV's ratings. Because I need SRW this might be more of a concern for me then someone who has DRW.
But the SB does not offer much of an inconvenience at all with my 5er. I have a manual slider, there are some nifty auto sliders available.
F350 PSD 4x4 SRW, BanksBrake, FOX res shocks, MagHytec, DP tuner, JohnWood tranny;
'63 hog; ChrisCraft Launch VP8.1 ;
3 hound dogs