If you wanted to be purely mercenary and compare the life effects of being LDS to JW you might be tempted to be LDS based upon the wider family support ( normally excellent youth support ) , women's organisation , singles efforts and the more hopeful nature of LDS theology ( almost zero Armageddon and end times discussion , low focus on bible memorisation for debate purposes and a more confident place in the world - less of a persecution complex.) The modern LDS church has become a desirable place for faith and family based believers but it was not always so. Just as JWs have sacrificed many of the community based life of the members ( good food at conventions, birthdays, Christmas, large gatherings etc.) and replaced these with more 'purity' based concepts so the LDS church is swinging the other way. During the 70s the LDS church got caught up in a wave of end time talk and became much stricter ( my mum wouldn't drink coke or buy sweets called wine gums in case she became addicted to caffeine or got a taste for alcohol by taste association ) especially regarding sex and music ( reaction as well to the era!) but it's gradually winding back those elements to a more 'do what you want in the bedroom' approach rather than 'sex only for kids and force yourself to find it icky while doing it' default.
Tithing is a big put off but again , for the services provided, it's not too bad and some people , once they've given up tea, coffee, alcohol and cigarettes might even come out on top. With the LDS welfare net thrown in ( you can get your bills paid and shopping bought while you struggle - humiliating though ) and the free labour you get ( meals when you are sick , missionaries to help dig your garden and someone normally has a van to help you move house) it's possibly a net gain.
People are of course unique and different and just like lovers that which attracts and the straws that break the camel's back are different. I knew one old guy join the JWs from our congregation due to loneliness (neglect and cliques are still rampant in LDS world despite best efforts to avoid them ) and a deaf guy found the JW deaf program more useful to our naive efforts ( though he thought JW teaching was bonkers) , but I baptised one exJW myself and had another join our church. The latter mentioned how difficult it was to leave the JWs because she would be shunned. Her family have indeed cut her out of their lives. It seems the barriers to JW to LDS conversion are much higher.
There is a tsunami of intellectual disaffection within the LDS church right now that is breaking it from within. It is so blatantly untrue ( historically) that increasingly the core members admit they stay because even if wrong its still a very safe and fulfilling lifestyle and to be fair the people, when they aren't being dogmatic preachers , are pretty awesome.
I suspect the JWs are going to suffer the same problem offset by the level of intellectual maturity they have coupled with Internet access ( so the Westernised portion will die off followed in a few decades by developing world stagnation and then shrinkage.)
Intellectual deconversion raises obvious barriers to future conversion in other faiths.