Rollers are ‘less boring’ that straight up riding a trainer, for sure. However, if you have a preplanned workout on the trainer, you can often go harder on it and as well if needed you can watch DVDs (training or entertainment) so it ends up being less boring than rollers.
E-motion rollers seem like the best option - they’ve got bumpers to at least stop you from rolling off the side, which is a big problem if you start zoning out on regular rollers, and as well the front-back float makes it impossible to jump off the front/back - ironically, that to me is by FAR the biggest problem with regular rollers since the moment you shift your weight, you risk jumping your bike off the front of the rollers (you’ll see what I’m talking about very quickly if you get rollers.)
Unfortunately, and it’s a BIG one in my opinion, E-motion rollers cost $700+! That’s a pretty hefty chunk of change, and they also take up a good deal of floor space (can’t fold down.)
Performance Bike TravelTrac rollers are $125ish in the store and work great, but have all the caveats I listed above. I prefer to not do intervals on my rollers as I can go harder on my trainer.
I also am of the opinion (which I would definitely add is not universally shared) that rollers don’t have an appreciable effect on my triathlon bike riding technique, if any. If you’re a sloppy rider that can’t hold a straight line to save your life, rollers will def help with that (but it’ll also be hard.) However, if you can hold a straight line (not hard), adding roller abilities won’t make that straight line a lot straighter. I analogize it to being able to do a wheelie - takes real skill and coordination, but in terms of riding faster and cleaner, the benefits are marginal compared to a regular cyclist. I will say that learning to accelerate on rollers is a great skill to have in close pack (criterium) riding since sudden accels would be dangerous - rollers absolutely force you to smoothen that pedal stroke or else you’ll jump off the front. In a tight pack with speed changes, this skill is very good -but in nondraft triathlon, it’s superfluouous, imo. (Others will definitely disagree!)
Probably the single best technique skill I’ve gained from my rollers is the looking back over my shoulder to check for cars move. I know you might think you can do it safely but on the rollers, you’ll see first hand how much sweve you have when you do this - it’s amazing how sloppy you will feel on rollers once your head turns. Once you can do this solidly on rollers, you definitely won’t endanger coriders when you check for cars by swevering left/right.
