The M94's prime virtue, at least in the later common 20" carbine versions, was that it was light and handy, and provided a sufficiently powerful ctg for deer and black bear, the 30-30. At its intro the 30-30 was the first smokeless sporting ctg. Deer were still hunted afoot primarily, especially in the east and south, and the modest ranges and sometimes thick and steep terrain were suited to the rifle and the 30 ctg.
But the bolt rifle and more powerful cartridges, and scope sights were gaining popularity with hunters and the carbine could not keep up. Drive and stalk hunting became less common, and now I seldom if ever see a M94 in the field. The Marlin holds on, barely, as they could be easly scoped and were offered more affordably for a period of time before the current "budget bolt rifles" hit the market.
Pros As stated light and handy, and with 7 million sold, ammo will be widely available for a long, long time. But, the Leverlution stuff is an answer to a question nobody asked. The .30-30 ctg will take deer, black bear handily, and has taken bigger game certainly. Heck, a 30-30 lever might even be a viable SD/PDW. The action, though not simple or accessable, is surprisingly rugged and reliable. The ctg has about 200 yd reach, but if truthful, few of us kill whitetails that far, and hitting with iron sights at that range, in field settings is not easy for most of us.
Cons. The rifle is not easily stripped, and must be cleaned from the muzzle. The traditional half cock safey requires the correct understanding and application, hence the birth of the safety equipped, lawyered up lever rifles, to me an abomination. The early versions are not easily scoped, so one must have young eyes to manage the bead and blade sights. A good answer is a peep sight, but nobody hunts peeps much anymore. MOderate power, sufficient for most of us, but if you are in elk, moose and big bear country, there are better answers.
I've owned and hunted several, and killed a handful of deer with them, but always ended up trading them away for something else. Now, they are out of production, essentially, and prices are climbing.