I think your best choice here would be Electrolux
First off, let's clear the air on one thing about vacuum filtration systems: Whether vac shops want to admit it or not, it's really the BAG that does the majority of the filtration in a bagged vacuum. All the exhaust filter is capturing, regardless if it is HEPA or something like Miele's Super Air Clean filter that comes with the bags, is the motor's carbon dust & super-fine dust your eyes cannot see. And even then, that's if you use paper bags....if you use HEPA Cloth bags, the chances of that superfine dust escaping the bag are next to impossible, assuming you are installing the bag correctly & taking care of the vacuum.
What I would suggest you do is take your Electrolux into a vac shop, have them remove the hose material from the machine end, & have them use it to put a new vinyl hose & hose handle on it to work with your wand. Also have them install new carbon brushes in the motor, chances are with it's age they are going to need replacement by now & it wouldn't hurt to take a armature seating stone to the motor to clean it up & make the brushes seat properly. You have a REALLY GOOD vacuum here, & one of Electrolux Canada's best models, even if you decide to upgrade to something new it would make a great car & garage vacuum.
When you take the vacuum in, have them sell you some HEPA Cloth Electrolux Style C bags to use with the vacuum when you take it home. Chances are, assuming your allergies are mild to moderate, the vacuum shouldn't be triggering your allergy symptoms when you are cleaning. If it does, then start to look at sealed HEPA vacuums.
When you are looking at new vacuums, beware of one thing: Don't just look at whether it's a sealed system, also make sure the HEPA filter is a certified TRUE HEPA filter. There are many vacuums that claim to have a HEPA filter in a sealed system, with a inferior quality HEPA filter. Shark is a perfect example of this.
As for the brands you suggested? Sebo, in my opinion, is not a good choice for allergy sufferers. Vacuumdevil has a comparison video on his channel, Performance Reviews, where he compares a Sebo E3 to a Miele C3 Brilliant. Notice how the Sebo does NOT make the particle counter go down to zero? It's because of their S Class filtration system that they claim is equivalent to HEPA. It's not! Their exhaust filter on that model is HEPA Cloth H11 bag material, not HEPA H12 or HEPA H13 pleated HEPA filters, & the Sebo D4 filter material looks to be very similar. While it may be indeed be a sealed system, the filtration material is the flaw in their system. Also note, their bags compared to Miele are inferior - they use 3 ply HEPA Cloth material, while Miele's bags are 9 ply HEPA Cloth material, that maintain the vacuum's power till it's 3/4 full, & the cost of bags & filters for both brands are comparable. Why settle for a vacuum with a inferior bag that costs the same? The prices that dealers want for comparable Miele & Sebo straight suction canisters is pretty much comparable as well. For that reason, I would rule out Sebo & focus on Miele.
I would also suggest looking into the Lindhaus Aria, Simplicity Wonder & Riccar Prima. All of these are high quality canisters, & you're likely to save some money as well over buying Miele. One thing I really like in particular about the Riccar/Simplicity canisters is the floor tool - it has a microfibre pad behind the bristles to pick up any fine dust the suction & bristles may have missed, it swivels just as nicely as Miele's Parquet Twister, & it also doesn't struggle with picking up large pieces, such as a dried pea, as the Miele tool does. One other area all three of these canisters shine over Miele is the quality of their electric hoses. If you do look at a model with a electric hose & compact powerhead, if you have any area rugs, you will notice right away the Miele electric hoses are short & stiff. Not so with these other 3 vacuums. The electric hoses are MUCH better quality than Miele, & more enjoyable to use. And all 3 of them have HEPA filters in a sealed system.
Best of luck to you in finding a good vacuum.
Rob
