*sigh*
Stelek is
partially right, but I guess I did a failure in holding winterman responsible for unsupported claims

math
8 Plague Marines ~ 184 pts
30 boyz ~ 180 pts
PM can't walk & shoot at 24, so orcs will likely choose their run move to begin in < 24 inches (note: you'd choose not to run into 18 like with the
NM example, silly thing but evident from the following).
PM get the first shot off.
a)
PM stay at > 18 so they can shoot at all:
8 shots, 16/3 hits, 8/3 wounds = 2.66 dead orcs, no cover, bigmek or anything, round to your favour: 27 remaining. Orcs move into < 18 to shoot back
54 shots, 18 hits, 6 wounds, 2 failed saves, 1 failed
fnp = 1 dead
PM
Orcs lost ~ 8.8% (expectancy values, variance better for the orcs like almost always)
PM lost ~ 12.5% ->
PM loose the first turn of shootout(!)
Knowing the average outcome of a), the
PM player then most likely proceeds to
b) move up to < 12 inches, double the shooting.
7
PM, 14 shots, 28/3 hits, 14/3 wounds for 4.66, say 5 dead boyz, 22 left (~73 %)
22 boyz, 44 shots, 14.66 hits, 4.88 wounds, 1.62 unsaved thats 0.81 dead
PM. Let's round this one up, too, for fairness ;-): 6
PM left (~75 %)
Almost on par, orcs had to decide beforehand:
b1) Orcs moved backward to < 18 but > 12 inches:
Same game as b) from now on,
PM win out small for numbers but big accounting leadership at some point.
b2) Orcs moved forward to now charge:
6
PM, 12 attacks, 6 hits, 3 wounds ~ 2.5 dead boyz for a total of 19.5 boyz left (hesitant to round here...)
19 Boyz, 38 attacks (
def. grenades), 19 hits, 6.33 wounds, 2.11 unsaved, 1.05 dead
PM. More gain for the boyz percentag-wise, though from now on they'd be on the decreasing branch of the
hth. Given time they'd eventually lose.

math ceased
So talking plain boyz, Stelek is actually right.
However, this is where 'target widening' as discussed beforehand would apply. Winterman noted that boyz would be bought as 26 shootas, 3 rockits, 1 claw nob (and still win out compared to Noise Marines given I didn't mess up the math).
30 boyz, 3 rockits, claw nob, bosspole = 250 pts
11
PM = 253 pts (can't find a worthy weapon upgrade that'd excel vs. orcs, though o.c. chances are that an all-comers list would feature maybe 10
PM 2
plas instead, diluting their anti-light inf. shooting)
Numbers change in that the boyz get the first shot and drop ~ 1
PM (5/6 actually) at 24 inches while losing ~ 4 boyz afterwards (roughly the same points wise).
At 18 inches they'd drop ~ 1.65
PM, now the
PM are in a pinch. I'll count 1.5 dead
PM to have workable numbers at all, with half a
PM rapid firing like 1 bolter shot...
Three possibilitys:
1. 8.5 rapid firing
PM either kill 5.66 ~ 6 boyz, worth roughly one and a half
PM. Still same strength for both partys left, talking percentages. But now the remaining orcs charge and the claw wins the fight,
PM lose
2. Or they choose to run and won't fire at all,
PM lose because of assault 1 or 2 weapons on the boyz.
3. Or they choose not to move up but stay at < 18 but > 12 to shoot once and
PM lose the shootout since killing only ~ 3 boyz.
Bottom line:
Pure shoota boyz lose in a firefight with
PM
Pure shoota boyz lose in a
hth with
PM
'Real' shoota boyz win in a firefight with
PM
'Real' shoota boyz win in
hth with
PM
(while still beeing able to beat Noise Marines, or take a luckshot at that random vehicle once in a while)
Noteworthy things:
1. The above is all about expectancy values. Variance favours large numbers even more. Doesn't bring much of a diff if 3 out of 3 bolter shots hit the boyz once in a while instead of 2. It does however change things quite a bit if the rockits got lucky and hit 2 out of 3 once in a while!
2. Boyz are pretty much good-to-go with 3 rockits & claw, while plasma or a fist would again reduce those
PM's chances.
3. In absence of a more resilent unit and regarding 5th Ed as a
KP-saving / troops preserving game I for one tend to agree with Stelek that Plague Marines are still by far the best unit for the job, anytime. Though sad that shoota boyz seem to be the better infantry no matter which unit I try to compare...
Over and out,
Khorneflakes
P.S.: 1 Big Shoota boy ~ 2 normal boyz.
3 shots, 1 hit, 2/3 wounds, 2/9 failed saves on a marine
4 shots, 4/3 hits, 2/3 wounds, 2/9 failed saves on a marine with double the number of boyz for unit size,
hth etc.
So no, big shootas do not excel at killing
Meq, maybe they do vs. expensive T 3/4 Save 5+ troops (are there any?), but shoota boyz shouldn't have any problems with those at first, so I guess the only benefit would be + 12 inches range. Since rockits have an effective range of 24 + 6 inches movement for a total of 30 (which isn't bad at all) I'd tend to call them the better upgrade for most, if not all, cases