I have a script that checks every 12 hours for domains that I am interested in. If one comes up it text messages my phone. Comes in handy and it is alot better than paying the $40 that some back ordering programs cost.
i'd say use all backorder services available to increase your chances
I've read that quite a few times, but I wouldn't do that simply because I can't afford it, it would be very very dear!
Of course if you're desperate in a way or in another, such as if you're making a living out of it, you might as well use all of them, or most of them.
Otherwise, particularly if you're after just very few names, I wouldn't consider that option.
if the name you are interested, you think no one will take it, try using those scripts or just monitor the domain and hand reg.
If the domain has high traffic and seems to be a valuable domain, even if you want to use backorder service, you might not get it, as there are some private domain catchers like buydomain catch for themselves.
If the domain you want may be popular, a backorder service greatly increases your chances of getting the domain. But if the domain is obscure or not very popular than a backorder service is just extra money.
It is better to be safe than sorry if you really want the domain so you should use a backorder service.