MOHAA Warchest must rest its laurels on its one excellent game (with two lesser add ons).
Accordingly the missions in MOHAA Warchest are mainly clandestine, behind the lines, with some incongruous returns of the main character to the main US battles of the war like Normandy and the Bulge. But almost always your character will be fighting alone, although nameless friendly AI troops will come and go. Also MOHAA suffers from being overtly US-centric, no doubt the Medal of Honor as a US heroism award limited the options. For me a lone American (in Spearhead) amidst the ruins of Berlin armed with Soviet weapons was just not right. COD at least gets the history mostly right. Eventually MOH Pacific would show that history and character development makes for a better experience.
I have recently replayed all three of the MOHAA Warchest games and reviewed each separately at GameSpot and will not go into detail here. Suffice to say that based on my subjective scores MOHAA (8.5) is the best in the Warchest compilation, with Spearhead (8.0) a close second and Breakthrough (7.0) a more distant third. As with many a series, the subsequent releases, while leveraging off the good name of the original release, are consecutively more disappointing.
MOHAA, the original game, is easily the standout game in the series. The game is far more immersive than its Spearhead and Breakthrough add-ons. The player's character is better developed and the reason for the missions undertaken are far better explained. Gameplay is identical for MOHAA and Spearhead. Breakthrough is of a departure from the tried and tested and less appealing as a result. Alas as Breakthrough is normally the last game you will play in your Warchest journey you may be left feeling rather deflated after being uplifted in the first game and parts of Spearhead.
OVERALL: MOHAA Warchest, or now MOH 10th Anniversary Edition, is the best way to get into the MOH WWII FPS series. Later MOH WWII games, that had cross-fertilised with the COD WWII series, like MOH Pacific and MOH Airborne are among the best WWII FPS games available. This Warchest compilation takes you back to the roots of WWII "historic" shooters and 2 good games out of 3 is still a good deal.