Towards AITowards AIToneBench

Grok 4.6 vs Muse Spark 1.3 (thinking)

Head-to-head on the Towards AI writing benchmark: same 10 real YouTube scripts, five runs each, scored blind by a three-family judge panel. Grok 4.6 leads overall, 86.6 to 82.6.

Grok 4.6
#27 Elo 2016 · 86.6/100
Muse Spark 1.3 (thinking)
#49 Elo 1699 · 82.6/100
Cost / script
$0.204 vs $0.041
Human baseline
90.2 Grok 4.6 falls below it · Muse Spark 1.3 (thinking) falls below it

The verdict

Grok 4.6 has the stronger current result: #27 at 2015.5 Elo and 86.61 overall, compared with Muse Spark 1.3 (thinking) at #49, 1699.2 Elo, and 82.63 overall. Their 95% Elo confidence intervals do not overlap, which supports the directional ordering (1961.70–2058.00 and 1653.10–1736.10). Grok 4.6 has its clearest metric edges in Length Adherence (88.03 versus 63.88) and Visual Cue Quality (86.63 versus 75.93). Muse Spark 1.3 (thinking) counters on Hook Strength (86.29 versus 80.81). At the measured run mix, Grok 4.6 costs $0.204 per article versus $0.041 for Muse Spark 1.3 (thinking); Muse Spark 1.3 (thinking) is the cheaper route. Both are closed-weight routes. On the current automated evidence, Grok 4.6 is the stronger default; Muse Spark 1.3 (thinking) remains a defensible choice when its specific strengths, price, or deployment profile matter more than the headline rank.

Pick Grok 4.6 when you prioritize the stronger current board result, length adherence, and visual cue quality.
Pick Muse Spark 1.3 (thinking) when you prioritize hook strength, and lower measured cost.

Metric by metric

Blue bars: Grok 4.6. Orange bars: Muse Spark 1.3 (thinking). Same 0–100 scale; the bold bar wins that metric.

Tone & Voice Match19% weight
87.9
85.0
Writing Craft & Clarity13% weight
86.5
84.1
Substance, Accuracy & Value15% weight
87.5
84.9
Continuity & Emotion14% weight
85.8
82.4
YouTube Best Practices12% weight
86.5
83.7
Hook Strength10% weight
80.8
86.3
Length Adherence8% weight
88.0
63.9
Slop Score (EQ-Bench + ours)5% weight
91.2
89.1
Visual Cue Quality4% weight
86.6
75.9

Everything else that differs

Grok 4.6Muse Spark 1.3 (thinking)
Overall / 10086.682.6
Writing Elo20161699
Run-to-run spread (± overall std)2.5302.770
Cost per script (USD)0.2040.041
Avg latency (s)243.178.0
Open weightsNoNo

Full scorecards: Grok 4.6 · Muse Spark 1.3 (thinking). How scoring works: methodology.

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