I'm guessing a lot of folks who've reviewed these books experienced them in the original printings, prior to Star Wars and the mass-popularization of space opera. I didn't- I "discovered" Doc in the late-80's as a teenager, and have become a huge fan. But heed the warnings of "camp" and "cheese": if there were an MST3K of books, his would be regular fodder. The gender stereotypes and roles as well as the frequent commission (and implicit condonement) of genocide by the heroes in particular are very hard to get past for a modern reader. Character development is non-existant (all protagonists are basically Boy Scouts or Girl Scouts), dialogue is awkward and unbelievably cheesy, genocide is repeatedly condoned, and the fact that the books were originally written as serials is painfully evident (almost every chapter ends with a CLIFFHANGER!). If you are a conesseur of camp, these books are a *rich* source of material.
But what I love about Doc's books is not rooted in irony: the incredible creativity in visualizing advanced technology, fast-forward and entertaining action plots, and the sheer scale of the "build up" within each book and from one book to another.
Technology: Although very quaint by modern standards (especially in "Skylark of Space"), put in context the creativity Doc displays in envisioning future technology is second to none. Not in terms of "accuracy", but in terms of their self-consistency and imaginativeness. Skylark was written pre-television, pre-laser, pre-NASA, and pre-nuke. What Doc built from that base is incredible, entertaining, and fun, viewed from the perspective that even relativity was a comparatively new theory when it was written (Doc obviously knew about it, and chose to ignore it). In "Skylark of Space", the result is spacesuits made out of leather, descriptions of how the spaceship's hull is fashioned from heavy steel, faster-than-light travel by simple accelertaion, and "energy beams" of different frequencies with different effects. I think Skylark of Space actually remains too tied to the technology of the day, but those shackles are unleashed in Skylark Three (the sequel) and Doc's vision really shines.
"Action": I understand that this book is the origin of spaceships shooting at each other. Doc's battle and action sequences need make no apologies for their age or context. This is why you put up with all the sexist attitudes, the bad speeches and the cheesy exclamation. Unless they are encountering the brief setbacks necessary to create some semblance of dramatic tension, Doc's heros kick so much alien bad guy butt it's amazing.
"Scale": Doc obviously is a big believer in the "orders of magnitude" theory of plot development. The formula is this: at the beginning of the book, the main characters are on top of the world, and their power seems nearly limitless. Then they nearly get their butts kicked by bad-guy aliens who are so much more powerful that the good guys look like gnats. Then the good guys bulk up (in technology, knowledge, etc...) to the point that the bad guys are completely and easily decimated. Repeat as often as necessary. What is amazing and enjoyable is how long Doc can keep this up: by the end of the series, literally whole galaxies are being destroyed. Yes, it's completely implausible, but dammit! It's fun!
Anyway, if you only are going to read one "Skylark" book, I'd actually recommend the sequel: Skylark Three. It's not very hard to get into the plot, and enough trappings of 30's earth technology have fallen away at that point to let Doc's real creativity shine.
In summary: Smith is a must-read for sci-fi buffs. Stick with it, and you will be rewarded. But don't expect any of your friends or family to enjoy it.