I've made many of the RQ's and LE's over the years and some of them have been outstanding but many have been good but a bit disappointing. Almost all of the whites have been excellent; the reds are where I have been disappointed with some, usually varietals. The best aspect of them is being able to make a varietal or blend wine that is generally not available in the regular kits. These kits are often sourced from grapes and vinyards not normally available to the kits companies so can be real gems. I find the blends have given me the best kits over the years.
Quite often, tasting events are sponsered by the wine companies to showcase these special offerings (they use commercial equivalents for these which can be hit or miss) and this can help you decide what you may like. Check to see if your LHBS may be doing one of these.
I've only recently started making the RJS Winery Series kits and these have been outstanding, better than almost all of the limited kits. I haven't made any En Primeurs or red Eclipses or any CellarCraft kits so can't comment on them.
For what it's worth, I have found over the years that the Spagnols red RQ's have given me better wines than the WinExpert red LE's with a few exceptions, but this could be attributed to the fact that the RQ's have had grapepacks and the LE's have not. The LE white wines have never disappointed me; I've only made a couple of white RQ's and they have been very good.
Regarding cost, the RQ and LE kits are less expensive here than the EP, Winery Series and Eclipse kits (by maybe $20-30, for regular prices) so they can be worthwhile investments.
My advice would be to check for tasting events, read the info on the kits when they are offered in a month or so, post on here for any members' experience with similar kits in the past, look at blends outside the norm (for instance there was an RQ called a Trio do Vinho Tinto 2-3 years ago that is a Portuguese blend of three grapes that is a great wine), make sure the red kits have a grapepack (except for say a Pinot Noir) and of course, be prepared to wait for the wine to mature to reach its true potential.