It really depends on your personality and eating habits.
I think a VLCD can be effective if you're someone who's slid into poor food choices maybe working long shifts, or in an environment where junk food is prevalent or if you've grown up around people who've made poor food choices, giving you distorted views about portion size, nutrition etc. In this case, a 'short sharp shock' diet can be really educational, and very motivating when weight comes off quickly. This can be enough to really change your whole perception of food. It feels like a fresh start.
But... if you're an emotional eater, or prone to binges (eating with very little pleasure), then I don't think it's a good idea. It makes your 'treat' foods seem even more important. It can encourage any binge/starve tendencies you might have; IMO, the discipline required to stick to a really reduced calorie diet is just the flipside of that total loss of control you feel when eating yourself sick. If you need to change the way you feel about food, VLC won't help. Plus, if you do too many weightloss/gain cycles, it can mess with your metabolism, pushing you to be dangerously restrictive to lose any weight at all.
I know it's very gratifying to see weight dropping off quickly, but I think it's important to be really honest with what's happening long-term. I'd say, if you've done VLCD two or three times, and have still regained weight after, it's time to say that it just doesn't work for you. It just means you have to rethink your approach. Don't say 'the diet worked, but...' -- the diet didn't work, if you're back where you started. It just seemed like it was working, for that moment when you hit goal weight, but beyond that it didn't help or change anything. Like a pair of shoes that look great in the shop, then fall apart in the first rainstorm or cut your feet to ribbons. Get something you can walk in for miles.