\begin{table}[h]
\centering
\small % Font size
\caption{Comprehensive performance comparison across all datasets and models.}
\label{tab:full_results}
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\resizebox{\textwidth}{!}{\begin{tabular}{@{}ll S[table-format=2.3(4)] S[table-format=2.3(4)] S[table-format=2.4(4)] S[table-format=2.4(4)]@{}}
\toprule
\textbf{Dataset} & \textbf{Model (Rep.)} & {Val RMSE} & {Val MAE} & {Test RMSE} & {Test MAE} \\
\midrule
\multirow{13}{*}{QM9} & GAT (ECFP) & 2.490 \pm 0.149 & 1.826 \pm 0.051 & 2.4370 \pm 0.2845 & 1.7870 \pm 0.1620 \\
 & GAT (SELFIES) & 1.898 \pm 0.072 & 1.493 \pm 0.048 & 1.8170 \pm 0.1360 & 1.4210 \pm 0.1135 \\
 & GAT (SMILES) & 1.896 \pm 0.071 & 1.488 \pm 0.052 & 1.7820 \pm 0.1350 & 1.4030 \pm 0.1105 \\
 & GCN (ECFP) & 2.483 \pm 0.171 & 1.811 \pm 0.085 & 2.4260 \pm 0.2380 & 1.8390 \pm 0.1615 \\
 & GCN (SELFIES) & 2.358 \pm 0.096 & 1.871 \pm 0.078 & 2.1550 \pm 0.1510 & 1.7270 \pm 0.1290 \\
 & GCN (SMILES) & 2.423 \pm 0.063 & 1.926 \pm 0.046 & 2.1260 \pm 0.1575 & 1.6980 \pm 0.1265 \\
 & GIN (ECFP) & 2.583 \pm 0.113 & 1.913 \pm 0.066 & 2.5470 \pm 0.2480 & 1.9270 \pm 0.1660 \\
 & GIN (SELFIES) & 1.883 \pm 0.081 & 1.489 \pm 0.068 & 1.8120 \pm 0.1300 & 1.4350 \pm 0.1060 \\
 & GIN (SMILES) & 1.876 \pm 0.063 & 1.492 \pm 0.058 & 1.8120 \pm 0.1395 & 1.4190 \pm 0.1085 \\
 & POLYATOMIC & 0.999 \pm 0.099 & 0.659 \pm 0.069 & 1.0480 \pm 0.1805 & 0.6510 \pm 0.0815 \\
 & SAGE (ECFP) & 2.516 \pm 0.165 & 1.836 \pm 0.086 & 2.4860 \pm 0.2580 & 1.8310 \pm 0.1640 \\
 & SAGE (SELFIES) & 1.561 \pm 0.031 & 1.206 \pm 0.029 & 1.4880 \pm 0.1180 & 1.1560 \pm 0.0915 \\
 & SAGE (SMILES) & 1.552 \pm 0.050 & 1.209 \pm 0.034 & 1.4290 \pm 0.1120 & 1.0890 \pm 0.0905 \\
\bottomrule
\end{tabular}
}
\end{table}